Idk what to do to calm myself

So there's this guy who I've known for a few years now and we see each other around town pretty often. I think I might like him, and I do get nervous when I'm around him... like actually really nervous.

Just today I saw him with some of his friends (who are girls and kinda scare me - who knows why) and I freaked out and ran to the bathroom and sat in there for a while.

I know I'm going to see him tomorrow too and I want to be able to stand calmly within twenty feet of him and be able to be myself and be... calm.

Any advice on how to not have a mini panic attack tomorrow?

Thanks (: