If you ask, "How do you know if you're an alcoholic?" then there is a good chance that you are an alcoholic.
I don't believe the advice that says, "If you can stop drinking for X number of days (30 seems to be a popular number) then you are probably not an alcoholic. MILLIONS of alcoholics have done this.
Try this. Have one drink EVERY day for 30 days. Only one. Do not skip a day. Come back here in 30 days and tell us if you did it. If you can't drink only one drink EVERY day AND not skip a day then you are probably an alcoholic.