Cherryxxx,
Yes, I have seen people drink too much for a long while, stop for a while, and then drink moderately. Those changes often occur at about your age. There is even a diagnosis in the psych manual for that kind of abusive drinker. Others never find the "moderate" switch and become alcoholic - we have to quit entirely or it does terrible things to us.
When I stopped drinking I felt as if I had lost my best friend. My friend that could make me feel better. (My problem was that my friend was ruining my health and all my other relationships, and was on track to ruin my career and cause legal problems). I WAS depressed. I got medical help for the depression, counseling and participation in a program of managing this disease I have. I didn't drink for over 14.5 years, then drank again for about a year and a half. Now I've stopped again for about a year and a half. When I need a friend I am forced to turn to people instead of my buddy "Leinie".
IMHO, you didn't do anything evil by drinking. I don't think you lose what you learn just because you had some cider. The point is what you do going forward. You might want to get a medical evaluation if you haven't had one to help you see what your situation is. Many people find a 12-step or other support group to be a godsend. (I love AA myself, but I wouldn't say it's for everyone, and it's sure no hotbed of mental health).
Best of luck to you
Fen