Desperately need some advice about friendship.?

I am a high school senior and all throughout the four years in high school, i have had trouble with friends and family. my family has always hurt me emotionally. and my friends also have come to treat me rudely, or they get closer to someone else and leave me out, or they find a boyfriend and leave me out. i have decided that i am tired to being close to my friends. my dad always says not to get close to people at school and i believe him now even though i should have before. i have decided that i no longer want to be close to anyone at school again because i am tired of being hurt over and over again. is this the right way to go with things? i feel like i need a really close friend to talk to because things arent so great at home, but my best friend is too wound up with her boyfriend and i she always tells me she cant spend time with me and always goes out with her boyfriend. what should i do?