Now a days, I cry a lot.In the toilet I will close the toilet door and cry for no reason! And I will also lock my room door and cry and pull my hair push everything onto the floor and I have the thinking of cutting myself but when I look back, I will think that its useless.and I'm 12... Is there something wrong with me ? I don't want to tell my parents they will think I'm dramatic or something like that. Please help me .

Sure, there's something wrong with your life. It doesn't mean there is 'something wrong with you.' You are unhappy, depressed, anxious, confused - all the feelings kids go through but a bit more so. You may even have hormonal surges that are out of the ordinary. Are you a boy or girl? If a girl, have your periods started?
There's a tiny chance of the beginning of some mental illness, but there's no point in thinking that way unless something changed a lot.
It would be best if you could sit down after dinner and tell your parents calmly that you are very depressed and need help. I know that's easy for me to say. If you can't, what about a teacher, school nurse, or relative?
Do you have any clue if there is anything that might be disturbing in your home life?