Backbeat, so sorry you got hit with this right at the time you're trying to stop. Instead of being rewarded for good behavior, you get slapped with that. No fun at all. It sounds like it wasn't a complete surprise, maybe the issues at work are part of why you're quitting drinking?
Tomorrow will be a better day. You can repair a damaged reputation. You have lots of support here so keep sharing and venting as you need to. This too shall pass as they say. Work isn't everything. Be not so busy making a living that you forget to make a life.