What do I do?

My mom was talking shit about my brother today.. It’s what she likes to do. My anxiety has been horrific the last couple days and I’ve just been in a bad mood. I asked her a question today and I couldn’t hear what she was saying and I replied “What did you say?” And she looked at me in disgust asking why I said it that way. I didn’t say it in a certain tone or anything, I just said it normally I guess.. this turned into a confrontation and I refused to argue back with her so I avoided the situation and went up to my room as she was shouting at me whilst going up the stairs. A couple minutes later, my brother came home from work and I overheard her speaking badly about me to him. She said “She can give it to you but she f*cking doesn’t like it when you give it back”. I’m really upset and angry. She’s been in a weird mood all day, even when I tried talking to her about going to therapy for my anxiety. She hates me talking about my mental health struggles to her. What do I do?