Advice!?

I feel absolutely horrible lately. This is a mixture of me being pregnant and my boyfriend treating me differently. For the last week or so no matter what I do it will always lead to my boyfriend snapping and shouting at me. I could breathe wrong around him while he’s playing his game and he’ll snap at me telling me I’m in the way and interrupting him. Before this I couldn’t have faulted him. What makes it worse is atm we’ve got his brother staying with us whilst his house gets sorted so it’s not like I can bring it up much. I tried before his brother arrived and he just told me I was overreacting. I don’t know what to do??