How to deal with being worthless?

Hi guys, I am an owner of a small Etsy shop and over the course of around 2 years have made 15 sales and earned a whopping 15 dollars all of which went back to Etsy to cover fees and marketing.

Besides that I am a web developer, but I've had an absolutely difficult time finding any work for the last 4 months.

Besides that I am also schizophrenic and often get burned out and sometimes am unable to work at all for weeks or even months.

With all of this in mind, I can't help but feel like I am utterly useless. It feels like whatever I can do, someone else will outcompete me and do it 10x better and faster. I wouldn't even mind being useless if not for the fact that in our society if you are not contributing anything substantial then you will not receive anything either. So despite my disabilities and weaknesses I continue to push on simply because I have no other choice.

I guess I'm just venting but also of course I'd like to hear some advice. How do you 'break through' in such an environment where the strong thrive and the weak don't while being of the weak?

Thank you.