What is wrong with me, specifically, and any cures?!

OK so I am a little depressed off and on lately!. I would be ecstatic one day then wake up in the worst mood ever then next!. Never really got angry, just sad!. NOT suicidal, NOT crying, just a down mood!. But it could last from 1-3 days!. Then I would repeat this!. I thought there could be some problems inside (chemical, mental, etc) but I had a blood test that turned out perfectly normal!. Now, the doc said I should stop getting drunk, even though I only get drunk maybe 2, 3 times a month!. I have been OK for a good week now!. And I haven't drank!.
School is a drag, but I'm not feeling stressed out by it!. Not compared to say, last year!.!.!.
I'm very worrysome when it comes to my feelings towards the girl that I like!.!.!. but I've been talking to her more this last weekend!.
And when I get sad I lose my appetite!.
Any ideas or suggestions!? Is the doc right!? What can I do to keep happy!?Www@Answer-Health@Com

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