This is good advice, obviously don't listen to ppl on Reddit about whether you have ADHD or not (that includes me), but reading your entire post you seem to exhibit some symptoms of it. Get some professional opinion and see what they can do for you.

As many have said you have a great support system and you can still turn things around. If you believe you have an addiction don't try to do it alone. If you want to get out of the ditch, find something to do and STICK to it. You may not feel like it but you have developed A LOT of skills and experience even when you feel you haven't been able to hold a job for long, those will help you in life as long as you get out and do something.

Good luck man.