I don't think you're insane. I think you're very aware of the problems you're facing and the difficulties with resolving them. You care about your job and your kids are a very important part of your life. That doesn't seem crazy to me at all.
It sounds like you're in a lot pain right now.
Could you call an anonymous helpline when you need to talk to someone and maybe get a referral for a therapist who is experienced with working with patients who self-harm? Or maybe it would be easier to talk to your doctor about what's going on when you know he is already aware that you cut yourself? Perhaps your doctor could help you with setting up an appointment with a therapist?