I so understand what you've been going through... I've never told my family about my depression, even when I needed to, until it was taken out of my hands and they were informed anyway. I too considered writing a letter but never got round to doing so... but if you think about it, writing everything in a letter gives you a great chance to say what you want, without interruption, where you can write exactly what you want in a logical fashion... and then you have the chance to go back and clarify anything... without having to face the reaction of your parents when you tell them. Instead, they can read the letter, calm down about it and discuss it. You could also write down just why you've been so reluctant to tell them. It's definitely not cheating... in fact I think it will be a lot easier foryou to write it down and tell them than to tell them to their faces. I know how it feels when you wonder just why you can't just tell them, but admitting this kind of thing is definitely hard... good luck