OP, it's not really in line with the forum rules to give you suggestions on specific suicide methods, as it could be interpreted as encouraging you to commit suicide. Basically, it's like saying this:
"I want to die."
"I know where you can find a gun."
I don't know what your life is like and maybe suicide is the best course of action. However, I think it's a mistake to rush this decision, because it's arguably the most important one in your life. I suggest that you think this through thoroughly. There may very well be other options than death, options you haven't thought of. If death turns out to be the only option, you should do some research and find a proper method so that you don't die in pain and agony or survive with severe disability. No matter what you decide to do, I think you should take the time to talk to people here. There are few communities where people are as compassionate and understanding as they are here. There are probably also forum members who struggle with the same or similar problems as you do.