As others have said, you should consider yourself kinda lucky to not have severe withdrawal effects, but don't let it kid you into thinking your body is fine with it. Different people react very differently. I know just one night drinking for me makes the next day complete and utter hell. I'm an emotional wreck, never mind after days or weeks on the booze.
Like you I drank to sleep, it's only recently i've discovered that I can actually sleep better without it. Not every night, but waking up a little tired is better than waking up with a horrible taste in your mouth and a pounding head!