I agree with Pacxiled. It really is a part of being 14. I am 16, and I remember that time period for me all to well. It was pretty much everything you described. Being a young teen is just hard especially because of your hormones. It will pass in time, but you also need to work on something to make yourself happy. I suggest getting a productive hobby of some sort... Use it as a form of outlet.
Don't know how long this has been going on, but I can tell you that this is what being 14 feels like sometimes. At that age the highs are higher, the lows lower, because of the strong hormonal surges going on. Just relax and my guess is it will pass. If it lasts for a long time, and if it seriously disrupts your life such as losing friends or big changes in weight, then I'd get concerned and find help.