Why not ask your teacher if you can write about suicide prevention by maintaining a well balanced life.
If you have to do this weekend, then pick a topic with a positive side and focus on that. For instance, what about focusing on crisis lines that help people return to their lives without the compulsion to do self injury. You could research a couple crisis lines and compare and contrast them and their approach.
Avoid the triggers, see the positive benefit this could have for you and others.