I used to be in a very similar predicament. I lived with my step mum on benefits and she was the type of person that was like OCD clean and the arguments about petty things were beyond annoying to the point they would just make you feel so down. I think she just liked to start an argument with me because I was an easy target for her anger and it was a very toxic relationship. Maybe your mum is the same. If so, you shouldn't be living together. There's certain people you can and can't live with and they need to suit your personality.

Whatever she says don't let her beat you down with it as she's obviously doing it to get a rise out of you and some attention because she's likely bored.
Someone putting you down constantly is not helping you - why should you help them?

Fair enough it's your mum but I know tons of people who've just straight up disowned their parents and don't ever talk to them because of their toxic reasoning for everything.

I don't even know my step mum anymore because she was psychologically tormenting me with really nasty comments and making me feel worthless. What kind of parent tells their kids they are worthless? One not worth having. Honestly when you cut the toxic people from your life things get so much better and you feel free to do what you want without any judgement or horrible comments. I'd work on getting out of there honestly and the depression will get better. If you're on carers allowance sitting around on that being depressed isn't going to help, I think you could do with getting into work and get a routine but I understand how hard that is to push yourself to do, but it can happen it's not completely inevitable.

Relationships are built on a mutual understanding that you appreciate one another - sticking around a toxic person isn't going to help you, family or not.

But yes I agree with the others, you should go to the doctors and at least give it a try. Anxiety/Depression groups on meetup.com aren't too bad to start with too. Everyones super nice at them and it does make you feel better about yourself.

Sorry if any of this sounds harsh, I don't actually intend it to be.