I can tell you b/c I was in your situation -- stuck at home, unemployed for about 6 years (the first time, before I had to move back 25 years later recently).

Your mom's mistreatment of you will never change. The only person we can change is ourselves and the way we react to really toxic people. In your case, since you are stuck at home with your mother, unable to work, I would seek out ways to get yourself out of the house. Go to free community events (free movies in the park, free museum events, etc., free concerts) in your city. Volunteer somewhere close enough on a convenient bus route that you can walk to and from your house. Go for walks. Listen to music. Write. Paint. Take pictures with your phone. Do something creative to distract yourself while you formulate a plan to move out and get a job.

Unfortunately your choices are limited right now. I know all about the panic attacks causing hives. I have that condition too.

Just ignore your mother. The less interaction you have with her, the better off you'll be. Just create the boundary of: I will only talk to my mother about the essentials of living together which are groceries, her work schedule, my schedule and that's it.

Separate yourself from her. Seek out alternative sources of emotional support where you can. Be it a community center, a free-walk in therapy counseling center. Here on PC. A phone support line. But do NOT rely on your dismissive mother for any emotional support.

I empathize with you 100% b/c I was in your shoes. And still am 26 years later unfortunately due to my own foolish choices. I lived with my mother for 6 years in my 20s, and now again, for almost a year in my late 40s. Very unpleasant but quite necessary due to my financial straits.

Try the suggestions I've listed. Set interpersonal boundaries with her. Do NOT seek her emotional support since she is so dismissive of your feelings already.

Make yourself a priority and take small steps to get yourself out of your house, away from your mother, albeit temporarily until you can get income from a job and find a way to move out.

Create a list. Create a timeline. Give yourself goals to follow and check them off one at a time. It will keep you distracted from her dismissive behavior, and keep you focused on creating a fulfilling life for yourself away from her.