Am I doing this wrong?

I am a 19 year old girl and my boyfriend and I broke up almost 4 months ago. I still really miss him even though he wont talk to me. I understand that he needs his space and I'm trying to give it to him but I am finding it really hard sometimes. I wish I could just find someone to be with so I wouldn't be so lonely. Should I try to find a new boyfriend, if that will even work, or should I try to build on myself and figure out why I can't move on as easily as he seems to be. He tells me he has a new girlfriend even though I have seen no evidence of it, although he did move 30 min away and I can't see him readily. I still have some contact, but not much. What do you think I should do and any advice into finding a new guy?