Maybe you can try to get away to peaceful places and relax when you can? Like go lay down at the park or something? I know a lot of people talk about mindfulness meditation too, but I don't do that. But it might be worth looking in to because I think it helps anxiety I just don't do it...

I don't know what your situation is but maybe you can talk with your mom about it when her boyfriend isn't around. Again, I don't know what the situation is so maybe that's bad advice, but connecting with people close to you and talking to them about it is definitely a good thing if you have someone you feel like you can talk to.