In blighttown, torches are where the ladder is.

Accept the mistake instead of judging it. Take piece of paper and write down the mistake you made and what you feel about it and what next are you going to do to either improve or avoid that situation. Use the pen and paper to bring the thought out of the mind onto the paper. You might be tempted to use screen/typing but trust me use the pen/paper. Once you do that just destroy the paper.