“Mental health ”

I have been using meth since childhood. I used to use and be able to put it down and it not bother me. Then I started shooting up a few times. Ok more than a few times. I asked someone to do it for me and they hit a nerve in the bend of my left arm. My arm went numb. Then after that the normal sensation that I used to get is gone. I used again and the heat went to my whole head so it was almost painful and my eyes went cross. Since then I have not been able to get high and the urge to keep trying is very strong despite the fact I know it won't work. I'm currently not using but I am concerned with how that whole thing went and wonder if I should be more aware of the people or if it's just mental and I don't understand why be addicted to something that I know doesn't work?