Fiance annoyed?

My fiance and I were forced to move in with his friends in a town he used to live with his ex. After getting here his attitude changed. He laughs at everything they say he talks to them about everything buy when I say something he snaps at me then later tries to kiss up. I blew it off but now I'm very upset. I can't do anything right. Maybe I'm over reacting but his behavior towards me lately is making me very depressed and anxious about our relationship. What should I do?