I messed up, please help me

My sort of ex-boyfriend and I are both 20 year old sophomores in college. All throughout freshman year last year, we had a constant thing. We made out a lot and knew we liked each other. However, I was too scared to get into another relationship as my first one in high school (as a senior into my freshman year of college) was awful.
He dated one girl for about a month at the beginning of this school year, but nothing came of it. We talked all the time and I knew he had still liked me all along. I still liked him, as well. Like I said, I was terrified. At the end of November, we made it official. I realized that I loved this man. We talked about how happy we were and how excited for the future we were.
Here's where it gets sad: I've been diagnosed with generalized anxiety disorder and depression. I am on medication for it, which I just now have increased dosage. With my last relationship, I was, well, crazy. I accused my ex of every thing in the book. I thought he liked my friends. I thought he was in love with his girl best friend. I checked his snap chat points, who he was following on twitter, etc. That ruined our relationship fast. It all stems back to my own personal insecurities. I see myself as ugly, extremely fat, not worth anything. Because of this, I worry. I know that everything I say and think is irrational, but somehow I can't stop myself.
When my new boyfriend and I started dating in November, everything was perfect. I wasn't worried about anything and hadn't been for a long time. But once we put the label "relationship" on it, the worries began. I accused him of liking one of our friends that he used to like. I accused him of sneaking around. I was crazy. Yesterday was the last straw for him. I argued all day.. I couldn't stop. I knew what I was doing was hurting him, but I was convinced that he didn't truly love me.
Today, we got together to talk and I exploded. I cried and stormed out a few times. I should've been calm. He told me how he's tried to help me get better, but he's tired. And he had never told me until that moment how upset he was with me. I was caught off guard. I knew what I was doing, but he was always so sincere to me. He told me he was done and left. He even changed his Facebook profile picture and his relationship status to "single." I texted him and he said we can talk in a couple days once things have calmed down.
I don't know what to do. I love this man so much, I can't lose him. He even told me he could see us being together forever at one point and that he loves me so much. I want to get better for him. How do I get him back?
I know you probably will think he shouldn't be with me, but I love him so much I would do anything. Please help.

The most important thing for you to do, whether this relationship ends or not, is to get help. To a large degree it sounds like these issues are somewhat out of your control. With help, though, you can change that. Trust me, it won't be easy and it will probably always be a bit of a struggle, but it will be worth it because you will be able to learn to balance things better and lead a relatively normal life.

I will say this, obviously not being in the situation none of us can comment for sure. However, it does sound like he put a sincere effort into understanding your issues and learning to deal with it and try to help you. The thing is, that is only reasonable to expect of somebody to a degree. You do need to get past this stuff on your own in whatever way that may take, be it on your own or with help. If he's given you no reason to believe you cannot trust him, then he does not deserve to be constantly treated like he has. Nobody does.

Please do not misunderstand. I am not saying any of this intending to blame you. This isn't your fault because I think it is safe to say you don't WANT to be like this. Just the fact that you can admit you have problems makes you better than some people (some I know personally, even). All the same, you need to learn how to better balance these things, and it is NOT a sign of weakness if you need help to do so. Whether or not we accept it, we all need help now and then.

Whether you wind up with this fella, or the relationship ends and you wind up with somebody else.... Whomever winds up being your significant other certainly doesn't deserve to have to deal with this sort of thing..... BUT, even more importantly, YOU don't deserve to have to deal with it. You CAN get over this, and when you do, you will feel like a whole new person. For the better, of course. Even better, it will better equip you to have a relationship and be able to keep it. You deserve happiness just as much as anybody else does. Sounds like your anxiety issues are making that impossible. About time, I think, that you kick your anxiety issues straight in the gonads once and for all. Good luck to you, friend.