i don't want to be the "omg same!!!" person, but i just want to say that i can relate and experience that a lot. maybe not the specifics, but yknow. im still working on this myself, but i think the best thing is to try to get a therapist. it's kind of their job to help with this self-doubt stuff, and they're most likely pretty used to it, so you can't really hurt them with it. about the brain always running thing, unfortunately i can't help much since that's also a very common problem with me. just try to take some sleeping pills and hope it works, i guess.. thankfully it seems to help with most, so there's a decent chance it's going to work for you. sorry for late reply, i'm eating oof-