I've said this before, but this is a good place to say it again: I'm an alcoholic. I haven't had a drink since August 29, 2005. Best 11 years of my life. I now work in a 28 day recovery center. I may be able to help find counselors/programs etc wherever you live. PM me if you want. Alcoholism is a disease, not a moral failure. It is quite capable of killing you, which is why your doctor wants you to come in and get your tests done. It is probable that if you go there and tell him the truth, you won't say anything he doesn't already know. I went in for a physical after I got sober, one of the docs first questions was "how much did you really drink?" When I told him he said "I knew you were lying to me."
Get some help and good luck to you.