You've said it here.
If you haven't even got a method yet, it probably won't work and you'll end up just hurting yourself.
I agree completely. I'm so sorry you feel this way right now. From observing others on this forum, a few important lessons have become clear.
1. Impulsive, unprepared attempts usually fail, and often contribute to a worsening of the situation — lasting health complications, involuntary commitment, strained relationships, etc.
2. The moments of extreme pain tend to dissipate. They always feel like they never will, but they always do.
3. You know when you're ready when you can make the decision with a clear head. At moments of extreme distress, we want to act out and may do things that aren't really in our best interest. This has happened to me so many times in so many different contexts.
I think staying here and chatting with us for a bit might indeed help for tonight. Then you can focus on preparing yourself properly for the moment you're absolutely sure.