Have you spoken to the doctor about the obsessive behaviours? Could be something underlying going on there.
As for the reward, have you explored much about cocaine addiction? Cocaine acts by binding to dopamine – reward pathway. That might explain alot, so it’s worth doing some reading.
Being moody and shut off could be “cravings” so it’s best starting to understand what they are and working out strategies in dealing with them
All of what you’ve said is understandable, and well done for trying to manage this alone. Have you not thought about going to your local drugs service for additional support?
It’s good you’re reaching out and trying, however you might want to work out what drove you to use in the first instance and go from there.
I would recommend going for some additional help.
Keep going