Your drawings look awesome. There is no "right" or "wrong" in art, only "better" and "best." (and "worst," but you're not anywhere near that end, so it's not really wort mentioning). Be kind to yourself and explore art.
So in regards to those torsos--they look good. Abs can form in a million different ways; they vary with each body. If you're not satisfied with them keep drawing, but realize that there's nothing "wrong" with your current pictures.
I don't know what in particular is causing your woes (just art frustration?) but I can recommend a good book about self-growth, Mindset by Dr. Carol Dweck. After the first half the book kind of falls into repeating itself (but making its point very well), so that's a small drawback, but it's easy and interesting to read and not too long. Mindset creates a subtle change in your thought pattern. I don't know if it's what you need, but I definitely view the world differently after reading it, and it's in a good way. So I'm recommending it!
You seem to recognize that mental health is just as important (probably more, actually!) as your art ability. So do yourself a favor, get a copy of the book and have some faith in yourself and time!