I'm 26 years old, have a below-average iq, depression and neurosis, didn't even finish high school and have been working all my life for minimum wage. I guess that in my situation it doesn't make sense to focus on a career, and I should just move from my home country which is relatively poor to a developed country (specifically from Poland to France) there to work also for something like minimum wage but this will still increase income 4 times. What do you think?
Is there anything you feel drawn to, in life in general, or in work? I would suggest following what you like and are interested in, and don't think about how much it helps or doesn't help other people, at least for as long is it's getting you down. If it helps you, that's a win! And if you want to go to France, go to France :)
By the way, it's okay to be stupid and useless, but I don't think you even are - you have been given money in exchange for your time and skills at all of those jobs you've done, for example. I'd agree with the therapy/self-help suggestion. Lots of therapists and techniques won't work for you, but keep trying, researching and experimenting because something almost certainly will. Some general advice that may or may not be applicable is to find more uplifting social contact, exercise more, and maybe volunteer for something in order to build skills and feel more useful and connected.