What's wrong with me?

Nothing really your just a teenager dude. Everybody gets like that. No one is happy all the time.

I'm the exact same! One minute I'm all happy having a laugh then literally 10 minutes later I'm depressed its like suddenly a black cloud just came over my sunshine if you understand? But what I had to do is look at my life and see what was wrong and change it! I was depressed on and off for 2 years and I still am but now I'm changing my life and things are ok there great compared to what they were but there's along way to go yet! So just think of why you do be depressed and what makes you happy! Nobody is happy 24/7 so you got to get to a point were your not depressed but your ok.

Sounds like manic depressive/ bi polar. Something to that effect. A mood disorder perhaps. Of course I would recommend seeing a doctor about that. But bi polar is characterized as major highs and lows that come on with no apparent triggers. Its like you're on top of the world and so manic that nothing can stop you, or you're so down in the dumps that you don't really even want to move. Is that how you feel? Usually it is extreme to be considered a mood disorder.
Not to be offensive, but do you use drugs? Illicit drug use can MAJORLY contribute to feelings like this, so if you don't do drugs, good. And keep it that way or you;ll feel worse.
Anyhow, I'm no doctor but I have been diagnosed manic depressive so I know what you might be going through. Best recommendations though will be given by a doctor though. Good Luck

I know exactly what you are talking about! Because I feel the same damn way at times! And as hard as it may sound. You just need a confidence boost! From personal experiences, you NEED to be around people who make you happy and are honest! If you are around people who mock you or make fun of you. You'd feel like crap! If you are around people who give you honest opinions and look over your "let-downs" and point out the goods in you. You'd be soo confident that you wouldn't feel crappy! Their comments will only make you realize that its okay to have flaws or whatnot. But your good qualities are better then your not-so-good-qualities!

I also agree with Money, If you keep on facing the periods of this mood swing. You should talk to someone you trust! A friend, a parent, anyone that can help.

But in whole, keep the thought of you being the "greatest thing ever created" and have good people around you to help you keep that confident up! But don't be cocky about it lol. Just make sure that you are happy and that you know that the "being happy" feeling is MUCH better then feeling crappy.

Good luck.

Nothing.

You're a teenager. Ever met one that wasn't moody/swung from "I'm invincible! " to "everything is going straight down the tubes! "?

You are in the process of discovering your self ready for the manhood, every man gone though it.

I am no doctor so all I can tell you is what I have personally experienced. My friends and I joke about my ego. I have always had a confidence, especially when I started dating more. I keep it in check and try my best not to come off as a cocky a-hole. I also have a mild form of depression. So I experience something similar to what you are talking about. My depression spurs from different things though. If it becomes more of an issue I would definitely think about talking to someone. I have had periods in my life when my friends see me and think I am this happy go lucky guy who doesn't have much of a care in the world and then once I got home BAM! I felt that I couldn't control my head or heart. You're gonna have to learn how to control it. Some people can do it on their own and some people need help. I hope this helps some what.