Hey Dizzyy and welcome to the BeyondBlue forums, and well done on admitting your illness - the first step to recovery is recognising and acknowledging your problem.
I remember thinking the exact same thing when I was first diagnosed - why do I have depression when nothing particularly bad or traumatic has happened to me? Why am I feeling like this when I have a particularly good life?
What you have to recognise is this: depression happens for all sorts of reasons. In my case, and quite likely yours, it has been triggered by a change in your thinking, not necessarily a change in my life. Somewhere along the line, all the positive thoughts turned negative. And that's okay, because you have the power to change them back again!
Don't be afraid to tell your parents! I am sure they will understand - perhaps guide them to the resources for carers here on the website to help them get a better idea of what you are going through, and have a look at the information together regarding the symptoms of depression and the various treatments.
Definately take a trip to the GP, as they will be able to give you an accurate diagnosis and therefore more accurate treatment options.
Keep your chin up, you won't feel like this forever!
Crystal
