It sounds a little like OCD to me. The thoughts of suicide sound like the obsession. The blurting out answers sounds like the compulsion. U say that u don't hear voices. Do you know that what you are doing is not normal? Do u try and hide it in public? Do u think you would ever follow through on these thoughts?

I agree with lee. Talk to a school counselor. But if u can, go to a psychologist or a psychiatrist. They can figure out what it wrong and medicate u or start u with therapy... There is a solution. You r in my thoughts...