What is wrong with my mother. Is she mentally unstable?

I'm 26, my brother is 22, and I have an even younger one who is 18. My 22 year brother recently bought a house and had been having his girlfriend spend the night a lot and my mom doesn't approve of it because she sees it as shacking up and she's a Christian. I have depression and anxiety issues and my mom sees me as a mental nut case, my 18 year brother bought the newest iPhone and my mom went off on him saying how he had no business buying a new phone when he doesn't even have a car. The difference between me and my brother is that my brother won't tolerate her going off on her, he was like " do you work my hours, is it your money. It's my money and none of your business. I work doubles all the time and I needed a phone my old one broke". I don't bother arguing with her cquse I don't need the extra stress, I already got enough health problems. The other day my mom was telling My 22 year old brother that she did not raise us to be this way. She was like " you shacking up, your brother buying a thousand dollar phone, and your sister is crazy". My 22 year old brother was like " I'm not even shacking up but I'll talk to you later mom" and he drove back to his house. My mom will make slick comments about me and my brother's significant others, especially my brother's girlfriend. She will be like " oh your girlfriend is cheating on you" and she will get upset if my brother doesn't want her coming over his house all the time cause he wants privacy.

I'm not sure being mad that someone is engaging in pre-marital sex and wasting money on a phone is indicative of a mental illness.

Sounds like your mother can't quite accept that her kids are full-fledged adults now, and are entitled to make their own decisions, claim their own successes, and live with their own mistakes.

If possible, plan to move out to a place of your own within the next few months. I think you'll find that your depression and anxiety issues will improve dramatically. Perhaps you can ask your brothers to band together and support you emotionally through this process.

Sounds like it