I am sorry you feel so hopeless. It's definitely difficult to carry on when you don't see hope. Good you are seeing a therapist to help you a little. In my experience, keep thinking about how you would be doing in the distant future, especially if you are not doing well now, can diminish your self-esteem significantly and debilitate you as a result. You want to do something now that you have the resources and the time to get a good job. That's a starting point. Now you need to explore what feasible options you have or what you skills that can help you.

Can I ask why are you studying math in particular? Did you have a goal in mind? Math is good, but in itself is abstract. Curiosity is good though. I like math. In the past I studied a lot of math. But math is most useful when it's applied. Like in Physics or Engineering. I am asking because you want to learn something that leads you to somewhere better within your reach and abilities, right?

Have you tried online teaching platforms like Udemy? You can found 1000s of online courses as recorded videos, and you can watch them at your pace (you will have access for life-time, and the instructors keep updating their courses), and at the end you get a certificate, which you may include in your resume. Every now and then they offer courses at low prices (~$10 or so), so, it's affordable. Explore the topics available. Google what the job of each topic entails and if you see yourself doing it. For example, you can explore the option of learning a computer programming language that is in demand and land a job without a college degree. You can study by yourself and do a couple of projects you can show to potential employers. Explore, and see if you like something.

I try to avoid giving advice here because I am not in a good place myself, and I am not sure I can benefit anyone. I am around your age, and have been unemployed for the last year, and have been struggling for years to land a good job. I am trying my best. It's tough, but I have to push through until I see the light, as someone told me once. Good luck