vicious cycles

So I just registered and I've vented to my ex's friend cause she's very easy going and understanding but seems like she just listened to what I had to say and didn't really help me in any way (not to sound conceited or anything) so here I am.

This is sort of long and I'll try to condense as much as I can will as much info.
I've date this girl for almost 4 years (shy of a month) and she called it quits on me. Why haven't I asked her to marry me for dating for so long is because I'm not financially secure and I'm 22 and I know I'll hear the "you're too young" comments but oh well.

She's 26 and she's the type that always saw herself marrying and having kids early so you can sort of understand.
The first year and a half was great like any other relationship but slowly went downhill. We would have arguements and I like to deal with them as soon as it happens. I don't like waste time over an argument or fight when it's time that could be spent to do anything together happily. Her on the other hand needs time away to think and figure out what to do next so it's extremely frustrating for me but I completely understand and I give her space. As time went by we would have a fight like any couple but then it got to the point that she would say "we're over" or "we need a break" and I would as her to reconsider. Now this happened often after being together for 3 years but now I'm pleading her to stay. It didn't help that she found some of my ex's pictures on my laptop and the reason for not deleting it was cause I barely used it after buying an iMac and deleting pictures isn't on the top of my list to-do. It progressed to me pleading her to stay whenever she wanted to leave and I know its a classic no-no and it gives her the "dominating" role which leads to her thinking she can do whatever she wishes now but I was hopelessly blinded at the time.

She says that she can't trust me and that I don't understand, that I don't get it.
We some how manage through it and continue dating but when we have a small fight she'll say how she can't trust me but then a couple days later we're still together like almost nothing happened. Small fights become big ones and by small I mean her getting mad cause I can't come up with a place to dine and then she wants to be driven home immediately.
Now last month she broke things off and I of course pleaded and told her how I felt and what she means to me but to no avail would she take me back. She said that we always fought and got back together and it was such a vicious cycle, which I totally agree but I can't help but think that if she wasn't so quick to be angry that we wouldn't have half of the fights we had. And I know that most of the problems we had we cause of myself but who's perfect?
She wanted to cut ties completely or go "cold turkey" as she would put it and some where down the road should our paths meet maybe we can try again as we've matured also. A week went by without talking. Then we start talking and we would do our usual routine of things ie: driving her to work, eating together, calling/texting, her staying the night etc. Thing is, she would tell me "this doesn't mean anything" or "we're not together" and I was fine with that cause I saw it as myself turning it into a relationship again. Another horrible mistake.

Which brings me to today...or at least 3 days ago. It was a long weekend and she wanted to go visit another city for the day which was only a 3hr drive. We rent a car cause I didn't want to drive my G35 coupe and we headed off. Everything was good, we were good we just weren't labelled as a couple even though we're doing everything a couple would do.
We come back to our city and she stays at my place for a bit then drive home in the rental. Now the rental car is due back the following day at 8am.
She has to drive it back and I follow her so she has a way home but I left my phone on silent and I slept until 9:20am so she drove the rental back but waited and called me exactly 19 times and then I woke. So I rush off to her thinking she's at her house and I call and asked if she returned the rental and she replies yes, so I tell her "I'm almost there" which was a lie obviously but I didn't want to tell her "I'm going the opposite direction so you'll have to wait even longer for me to pick you up" cause I know she's already pissed for waiting and if she gets mad at little things then her waiting for more than an hour wouldn't end too well. She replies with attitude "how?! how are you almost here when I called 5 minutes ago. Don't speed!" and I gave attitude back saying "fine. I'll call you when I'm there then" and she hangs up. I shouldn't have responded that way but when someone gives you attitude it's like an impulse to give it back.

I finally get there and I say how sorry I am and how bad I feel for making her wait for so long and she isn't responsive. Couple minutes later she lets it out on me asking why didn't I pick (it was on silent) and why was it on silent. Now I didn't have an explanation for this and usually I don' put it on silent and she knows this but I honestly had no idea why I put it on silent. Me saying "i don't know" would only piss her off more but I said it anyways cause I really didn't know. So she's pissed even more and goes on so say "I understand that you were tired the night before so you sleeping in didn't bother me but you giving me attitude when I'm the one that should be pissed isn't right. Where do you get the right to give me attitude when I've been waiting for how long and now you tell me you don't know why your phone is on silent?!?!"

She's extremely pissed and tells me to f*** off and I drive her home. That was 3 days ago and here I am now. Yesterday I tried to talk to her, ask her how her day was, if she worked but then she asked me why am I trying to small talk. I tell her cause I feel bad and I shouldn't have given attitude and that I'm sorry. She doesn't reply back. Later I tell her that I'm sorry again and I'll wait until she's ready. She replies "Don't. Today I asked if I could see her and she says "No." I try again later and tell her how I feel again and that I'm sorry and that I'll wait. She tells me "you don't get it" and that she's "so good and done and she is extremely exhausted from all this". She goes on to say that we aren't even together and she can't even stand me so why the hell would she want anything to do with me now. I told her I'd still wait and she just says "Then waste your time."

I'm at a loss now. I've been with her for practically 4 years and I don't want that to go to waste. I understand that people fall out of love and things just don't work out after a while but I believe entirely that she's the one and if she stayed with me for this long and also stayed but not as a couple then doesn't that mean something. I don't know how to approach this. A part of me thinks that if I just wait she'll eventually call and slowly things go back to normal but there will always be that one fight or argument that will lead to this all over again. The other part of me thinks that I should just quit after trying for all these years and move on, it's just ridiculously hard to do after being in a relationship for 4 years and having that someone there when you get home and mentally I'm not strong at all to endure a break-up. And if this does some how work out I don't know how to stop this cycle of getting back together and taking breaks.


Story of my life lol.
Any advice would be beneficial and again I apologize for the length