@Handsley sounds like you are really down in the dumps and it always makes me sad to hear of anyone feeling that way. Anyone who has been in a depressed state knows how painful it can be. One of the benefits of having had a major depression in my life is that it opened my mind from the "oh come on, just snap out of it" mentality. I thought if I heard my mother tell me that one more time I was going to strangle her.
Don't give up on your son. I don't know how old he is, but maybe he just hasn't had the kind of experience in life yet like the one I had to go through to open my eyes and become more sympathetic. In all likelihood he will regret behaving in a hateful way towards you, although I know that doesn't make the hurt you are feeling today any less.
Even though I don't know you well, I know that you are not useless. The ability to lift heavy objects has no bearing on your value. Ugh, I remember having such similar thoughts. I had lost my BF of 13 years, my home, my job, and shortly thereafter my savings. Totally lost sight of the light at the end of the tunnel.
Twelve years ago.
One of the best ways to make headway on climbing out of the hole is to find a cause outside of yourself. Find someone or something that could use some help. Doesn't have to be a major achievement, you don't need to save the world (although we really need you to right now). It could be as small as answering questions, walking a dog, tutoring a kid; wherever your interests lead you. All it takes are a few small victories and you will be amazed at how it can lift your spirits to have something concrete that proves you have worth.
We all know you already do, it's just a matter of learning it for yourself.