need advice

my son is 9 months old and i havent been able to speak with his father since the day i told him i was pregnant. he changed his number and has been hiding from me ever since. i know where he is but i dont go to him because i dont really know what to say and i know i will probably break down. i dont want to cause a big scene. i need help with a few things so this is where i am starting. the first thing is i havent filed for child support yet because i dont know if that is best. absolutely we could use the money, im so broke, but do i want him in our lives if he is just going to be a continual let down to my son? is it better to just leave things alone or should i stir up the pot? i thought maybe he would come around if he has a monthly reminder that he is a dad.. any thoughts?
the second thing is more about me. i spent my entire pregnancy alone. i was so sad that i wasnt going to be able to give my baby a father and i was so lonely throughout it all. guys would try to date me because u think u can do it.. it seems rational. until you actually get into things.. its more than most people want to take on in a new relationship. anyway now that i have gone through all this and i have a happy wonderful son. i find myself pushing everyone away. i have always been like that, never let anyone in too close to begin with, but now i am actually destroying my relationships as fast as i can. and i dont care. i just dont want to ever go through all that pain again. and im not a weak person dont get me wrong. i am stronger than most i feel but im just so broken... im not very good at describing things so hopefully i am telling the right details. i just dont know how to get over it. i cant even talk to guys and im so lonely. i have zero self esteem and hang out with people who use me. i cant think about the future or make plans to get on with my life. its crazy. i think at first it was postpartum because i was also really depressed but im not sad anymore. just scared. and that is not like me at all. how do i get over this broken heart so i can stop destroying everything in my path?