How can I painlessly end my life?

I am a 17 year old teen. I know many of you would be weary to answer this question. I used to be a straight A student two years ago. Now, as my junior year is coming to an end, I am not going to graduate high school. I hate myself for it. Hate is a strong word and I have never used it before except for this context. Every hope and dream I had of going to college is ruined, I couldn't afford it even if I wanted to. now I just want to do myself in. I have prepared notes for every family member detailing my reasons for departure. This is something I have thought about for long enough to know it's what i want. Please, if someone could just help.