If you know your parents will be understanding and willing to listen, then I think you should tell them. They probably don't know just how bad you're feeling. I'd be horrified if someone I love is considering committing suicide and I didn't know about it. And I think you should talk to them about your college situation too. Let them know how unhappy you are with it. I can relate to that a bit too, actually. I was too immature at seventeen to choose the 'right' subject to study at college and although I stuck to it and graduated, I still regret the decision, many times.
I hope things get better for you, nonnie. And rant all you want :) *hug*