Try not to drink anything at all for 30 days. If you think about it a lot during those 30 days then you are most likely an alcoholic. People who are not alcoholic do not spend any time at all wondering if they are. (Like someone else said)
If drinking is causing ANY problems in your life, then stop drinking. (especially health problems) If you have difficulty not stopping drinking, get support in AA, here, etc.etc.etc.
Good luck!