After 5 years i still love her?

it was years ago that i was in a relationship with this gorgeous amazing girl i was young and stupid and cheated on her with someone else, she forgave me and we kept dating, i had to move to england with my mom and lil brother and so it ended. we tried the long distance thing, i told her once i was going to portugal (where we lived) to see her but got muged that day and ended up not going she didnt come online for a while and i could reach her i think she chose not to pick up, finaly we started talking again and a second time we agreed to meet in portugal, this time there was no chance of me going i just said that in order to buy time or something. anyway she and i stoped talkin months later i see her on a hi5 thing with her new boyfriend, she's had 2 by my count and its been with one for more than a year. i'm happy for her seriously really happy she laughs on pictures and everything so i figure shes happy. thing is i love her, i've gone on dates and people have had intrest but i just cant, i think about her all the time. i tought about killing myself more than once and i cant see my self caring for noone else as childish as it may seem. i told her how i felt about 2 years ago (no suicide talk) and she said she didnt feel the same way and that she was happy and in love. i think im paying for having cheated and i know im young 24 and that got my life ahead of me but i think that what would send me to the grave would be to find out she's gettin married or pregnant. i have nightmares about that. i dont know what to do recently they've become more consistant i stay awake untill 3,4 o clock at night pacing back and forth in my living room and its like i feel this adrenaline like rage thing fluid going through my veins i try not to cry but its in there you know. pretty sure noone can help this but to be honest figure i'd write. could be wrong here so if you got any ideas how to solve this let me know? thank you