Hey there!
Have you thought about getting any help or advice from people you know, such as friends, family or a teacher?
If you do, I think that's your first step into getting out of what you're feeling at the moment.
If you don't, another option is to go see a counsellor. If you're still at School or College I'm sure they will have their own system where they can set you up to see somebody.
And lastly, there's a whole load of people, including myself, on here who you can talk too.
At this moment in time, suicide is what you feel like you want. But this time tomorrow, next week, month, a few months, even a year! You don't know if you're gonna feel like that then, and you don't want the way you're feeling now to chuck away the rest of your life.
P.S "When you feel like giving up, remember why you held on for so long in the first place" Your own advice