she's losing passion in our relationship :(

ok guys i need some help.
a little background first. i met my current gf 5yrs ago in high school and we got together 2yrs after that. now i know i was an ass then so you guys don't have to remind me after you read this :P
anyway, my dad never approved of me having a gf so i hid our relationship from him and had to talk to her and meet up behind his back. throughout this whole time she was very supportive and would drop everything she's doing and call me whenever i'm free. I was so arrogant thinking i have a girl crazy about me and i didn't realize that she has needs too. anyway a year into this, one of her guy friends told her he had feelings for her and i would notice that she'd stay up till like 3am just talking to him. i got extremely jealous and decided to do more loving things so she'd know what she'd be missing if she left me. Afterwards she told me she wasn't interested in that guy and she's just proven the fact that i only try hard and show love when i'm threatened by her leaving. i realized then i was being an ass and apologized, asked for one more chance. she didn't hesitate in giving me another chance.

we then went to London together for university, where we lived together. things were great for a while, considering we were together all the time and i didn't have to hide from any one. anyway, after our 1st year we had to go back to Saudi Arabia for the summer, cause thats were our parents lived. Things got complicated again and I was making the same mistakes. I told her that I do love her and that i'm just a little slow but i love her with all i have. she told me that its not enough, that she gives me so much more and i give barely anything in return. well i apologized, did more lovey stuff and she forgave me again.

we went to London for our 2nd year and things were okay again. but yet again we had to come back to Saudi. She told me that this time she doesn't expect anything from me so she won't be disappointed. and she has been calling less and been lesser clingy. anyway to my problem atm. when my gf is PMS-ing, its extreme. she knows it too and she apologizes later for how she acts. anyway last week she was PMs-ing and i didn't notice. the day before yesterday she called me, and i was at a friends place and was a little occupied cause i was trying to make him feel better as he was devastated about his divorce. anyway i talked to her but since i was busy i told her i'll call again later. that ticked her off and she started yelling at me that i don't give her enough attention and that i'm not passionate and hung up. i know this will pass but i just want to know how can i make the next few days a little better. any ideas on what i can do so she won't be so pissed at me?

another problem is that she says i always make the same mistakes because i don't really love her. she says that if i did, she wouldn't have to tell me how to make things right and that it would just come to me naturally. the problem is, it doesn't. i've noticed that whenever she's pissed is only the times i feel inspired to write poems and do something extra-ordinary. its not fair and not right to her. she says i lack passion in our relationship and that she's tried so hard with me that she's lost her passion. the truth is i really do love her, more than anything and i can't imagine living without her. its just that i always end up messing things up and for some reason i never learn. i really love this girl and i want to make this work for the long run. i want her to feel how much i love her.

i cant do much while we're in Saudi as men and women who are not related should not be together. we're going back to London in 3wks and have no intentions of returning back to Saudi, so I tell her that we'll be fine when we leave this place. she just says that she always feels like she's number 2 in my life and she hates it. i dont know what to do really. what she says is true, i do seem to do more stuff when shes pissed at me than when we're ok with each other. all i do is think about her and how to make her happy. shes my first thought in the morning and my last at night. when she's happy, i'm over the moon and when she's crying, i die inside. i just want to make her happy but i cant seem to do it right.

now shes not talking to me and i feel that she's losing her passion in me. she says she wont leave me cause she loves me too much but shes just tired of our relationship. it hurt me a lot but i know im the one at fault again. i hope my post makes sense and wasn't all over the place. i know i'm rambling but i just need a little advice. if you have any questions i'll gladly answer.

Thanks for any responses