True Friends??

I have a lot of trouble trying to believe in a true friend because all of mine have left me and i always end up feeling alone. i don't really have a problem making FRIENDS because i have plenty of them. Everyone even says i'm one of the nicest, funniest girls, but its the BEST friends i have a hard time with. They always leave me,two of my best friends left me for cheerleaders and then one of my best friend started to hang out with her boyfriend and his friends more. Whenever I open up to people i always end up getting hurt. Especially during this time when someone i considered to be the me only parent died, my dad lost his temper and hit me, and i ran away all in the same week of Christmas. No one was really there for me even then. I secretly cry a lot but put on a happy face for everyone now. i don't know, what's wrong with me, why can't i make really tru best friends who will really be there for me? i'm sick of being so alone.