My Mistake : Chosing The Wrong Person As Friend And Being Over Sensitive

I had very few friends since childhood and oversensitive. Making new friends has always been very tough for me. I am not socialising type of person but i was very fond of the few friends i had . Things changed when i went to a new highschool. All my friends were left behind .Then i made a new friend... .I get deeply attached to people whom i care for. But this friendship was almost one sided. The time we became friends , she was going through a break up. So i had that soft corner, that empathy for her.Maybe this was the reason behind the strong attachment. I did all that i could do for her as a friend. Things were going fine. We decided to go to the same colleg for higher studies.We had entrance exams of various colleges which we need to crack to get admission. When the results came out i had two choices. I had cleared the exams of a reputed college.I could go to the same college as her or i could go to the reputed college . I chose to be with my friend . It was a decision i will always regret in my life. When we came to this new college in this new place i began to see things in the right perspective. In our friendship everything was only about her.. her wish, her mood, her likes and dislikes, her emotions.Now and then she used to do things which would hurt me. I never told or complained but I used to cry silently sometimes. Then she got a boyfriend and ignored me. after a year again her breakup. I was always there to support her and comfort her. In the meantime many things happened. she did many things which hurt me. Each time she said sorry i would forgive her.A common friend of ours told me that she is was spreading wrong thing about me but i ignored it thinking that she could never do such thing. i Considered her my best friend.One day i overheard her telling to someone on phone backbitching about me. I still remember each word that she spoke about me. I cried the whole night . When i mentioned it to her the next day she said sorry and said that she did not actually mean what she said last night on phone. I forgave her.she went her usual way , that unconcerned , self centered way and i as usual expected that she would change one day. Six months before, something happened which i wont go in details . but that i did not want to endure that anymore.I complained, we had a quarrel and that was the end . we didnt talk to each other after that...
For months I was very upset. I became more silent than before. Everytime we crossed each other I felt a pain.I was not able to get over that attachment. Day n nght that samething crossed my mind again and again.That feeling i cant explain in words.But slowly i understood that it is better to be alone than to be with people who make you feel lonely.
It was a good change which should have happend much before. now I am free from that emotional turmoil.Till now i have not been able to completely detatch her from my mind but i hope one day i will... I prefer to be alone and be happy with myself instead of depending on others for happiness.I cant control my sensitivity so i prefer to hold myself in my protected shell.