I know how you feel, trust me. And from the sound of it you are a teenager going through all the hormonic periods of your life. I've had that period too, but now I'm past it and almost back to normal. It's been really hard for me back then and I would find myself crying and tearing up randomly. But you need to try and learn to control your emotions. Not to force yourself to be happy (because that makes you even more depressed) but to try and look at the brighter side of things. Sometimes having a stress ball helps too (though once I used a stress ball when I was really angry and I ripped it in half... :/).
I also know what it's like for others to see you going through your fase (Lilly's like that right now, no offence Lilly). It really isn't nice. Though don't push everything you feel down and keep it bottled up, that means you might snap at any moment. Try to talk it out with your friends and family. And it helps when you have something to do to distract you. (Don't sit in the dark all alone feeling sorry for yourself, trust me I've tried that, didn't help.) Basically, suck it up and get over it, or try to at least. Because that fase will be over before you know it.
Hope it helps....
Love, Vi xx