Hi, I am a lot older than you but I can relate because of your past to what is going probably on in you (Iwent through some shitty stuff too).
I know it is not at all easy to simpy go and talk to him when you are all nervose about it.
Good to know is that it is most probably just fear fear being hurt fear being rejected.
To the fear of being rejected that happen when we set our own value based on fact if somebody likes us or not.if we like somebody who doesn tlike us the same way we ted to think that we are not good enoug. But it is not true, making the first step is bit similar to asking somebody if he would like to play with you tenis…if he doesn’t well no harm happend simpy go look for another game partner. 
And the fear of being hurt in the relationship - well this one is tricky, because being honest you will sooner or later probably get hurt… relationships are rarely all day sunshine. So everybody mus inside himself evaluate if the need for protecting themself or the will to experience relationship is bigger.
What I would sugest is to talk to him, you do not need immediatelly open your heart but be friendly.because if you are avoiding him he probably thinks you are not even interested in talking to him.
And see where it brings you if you will get the corage to make the first step. 
well good luck anyway and lots of love. 