Chocolate :P
No, seriously, if you're genuinely concerned that there's something wrong, try talking to a councellor, or even to you GP. I felt similar to you, and I was diagnosed with depression last November. I just thought I was moody!
Councelling didn't work for me, so I tried the anti-depressants, and while they made me happy, I didn't like being on them, and literally forced myself to get better and come off them.
I know it sucks feeling like pooh for no reason, and unless people have felt it themselves they don't understand it. My mom used to just tell me to cheer up, and used to get quite angry with me.
If you need someone to talk to, you can always PM me. Not great with solutions, but I can be a listening point if you like?
I hope things get better for you hun
Bec