I can't forget the girl i loved and i don't know how to get off this situation?

4 years ago , i was attracted by a girl in my school and i liked her so much : the way she talk , walk, she act .. so i worked hard to win her intention in order to be my girl friend and i figured out that is a very shy girl and polite so i made a decision to go talk to her and express my feelings in a respectful and polite way ..that's way someday i walked to her and i asked to known each other as a result she was surprised by my question and replied let's be friend .. so day after day the intention get more close and i was very satisfied because i had had a plan .. but unfortunately am emergence situation happened (family problem) , in fact my life was turned upside down and i was depressed even i hated every person and i didn't wanted to see or talk to anybody moreover she sent me a message by my friend asking me if i can talk to her but i didn't replied (I Know i am fool but i can't blame my self i was in a hard period ).. after all two years later i was in a recovering mood and i felt ok about everything i ped to university and i start to forget her because of my unsuccessful plan .. but surprisingly she came to my university and i was so scared what she will say and behave with me so i start to avoid her and hide in places that she can't see me furthermore when i looked in her i eyes i didn't saw any feeling of blames or angry just only eagerness even more someday she stand up next to me to say something but i escaped running and i don't know why !!!!.. all these action are disturbed my moral situation which were in way to cure and became health as a result affected my life and i was in way to be depressed again .. in addition i was had some feeling about here in that time but i wasn't thinking well and i don't know what to say to her so i ped the whole year like that until i graduated and i ped to another universities in another state ... but after two years ( means now) , thank god i ped all difficulty and all my problems are resolved i started to continue my life and started to make new friends be sociable again .. but someday i remembered her and i remembered my foolish and insane act i made about her (ignore , escaping from her ..) so i asked my friends if she is in good life but i had informations that she had been with two successive relationships and two of them are failed .. so i wondered if what she's ping now is because of me ..that's why ,about some months i am thinking to write her a letter not asking to be friend again but explaining my situation that i didn't wanted one day to harm her and always i have about her feelings of respect and "love" but some obstacles forced me to take another direction ..but after meanwhile i change my mind supposing that she forgot me and she don't have any feelings about me right now and also i am no longer know how she behave ..for that's reasons i write these sentences asking for help and advice because suresly i can't get her out of my head even i tried many times to get over it but couldn't ..please help