Flagged or altered clearance

Years ago I tested positive for marijuana and my career ended with AF Reserve. I was told it be a general discharge, although I never received anything in the mail. Left the unit with referral EPR, bad military record and flagged security clearance. I have gotten my act together since then and my question is can I ever re-enlist in the service again? or ever to re-gain a clean clearance status for that matter?

If you have any shot at all, it will be with the Army National Guard.