I also cry. A lot. Whenever I am alone I just sit or stand there and cry my heart out. I don't know why. I just do and I can't stop it. Help?
Ohkay... Wow. Um, if you're still here (Since it's been a while since you posted this), I can attempt to help... Okay, one thing is you have to stop cutting. It's really not good. It's just a permanent reminder of your feelings. Those scars aren't releasing anything. Trust me. Crying is better, because crying is actually sort of good for you with the hormones it releases, but it would be better if you didn't have to cry even, but we can target that problem some other time.
Over the top school work is a big issue for me too, especially with GSCE's etc. If you're really struggling, try talking to teachers and staff at the school, briefly explain your problem, but don't go into detail with any other problems if you don't have confidence in telling them. I made the mistake of trusting my school.
But yes, if you're not happy, and you don't want anyone finding out, it might sound tough, but you have to stop. Try doing other things you enjoy. I either write or draw now. Or play video games, usually. But I'm coming out of depression, so... Also, if you're not sleeping, it helps to sleep. And keep yourself relatively busy, so you don't over think. Over thinking is bad, but just now and then think about things, it can be very eye opening.
I hope I've helped, although I have abysmal self esteem because I've been told countless times I'm useless and unhelpful... So sorry if I didn't help...