Sorry to hear about your relapse. After I woke up one morning questioning why my car had almost 10k in damage I swore I would never touch the garbage again but the fact of the matter is that Ambien is contraindicated in those with substance abuse.
Any controlled substance is technically contraindicated in those with a hx of substance abuse but Ambien is even more so due to it's hypnotic effects. Ambien and alcohol are both GABA agonists and the threshold effects between the two are indistinguishable. If you can't be trusted to get a buzz from a few drinks and keep it there you can't be trusted the feel the indistinguishable buzz from Ambien and leave it alone.
No point in crying over spilled milk but if your Physician knows of your history and prescribed you Ambien without at a minimum informing you of the significant risks I would seek out a new doctor.