I'm worried that I might be depressed, SAD in particular?

I've been disconnected from all my friends for awhile, and was thinking that it was just a phase but it has gotten worse. I am always craving sugars and breads, waking up in the middle of the night and not being able to fall asleep. I'm irritable ALL of the time, and have headaches and backaches a lot. I am normally just a loud and fun teenager, but I've been really quiet for the last couple months. I don't even remember the last time that I laughed.

I've definitely lost interest in my normal day activities. I don't like to read, dance, hang out with friends, or even listen to music. The only thing that I haven't become apathetic about is my grades in school.

The worst thing has been the crying. I don't normally cry, but I have cried almost 15 times in the last week. I broke down into tears during lunch for absolutely no reason. My friends are worried about me, but because I haven't really been talking to them they didn't know what was going on. I finally broke down on the phone with one of my friends last night and was crying and telling her about how I couldn't be friends with her because she ignores me. :Later I realized that it was actually me ignoring her. I guess I just feel dull all the time and don't know what to do. Other depression symptoms that I have: lose interest in things you used to love, too much sleep, feeling empty/guilty/hopeless, slowing down, neglecting things that I normally do (for instance, I am usually uber picky about keeping my room neat, but it has become a pigs area) difficulty making decisions, inability to concentrate, loss of sexual desire and warm feelings.

I am really worried about myself, but want to see what other people think before I try to talk to the school counselor. Thank you so much.