How do i forget the past and think for the future?

It'll be better: Great question. When your mind goes back to the past, say, 'What did I LEARN?' Where you were wronged, forgive and decide whether those persons will still be part of your life. Make up for wrongs you did others if you can & let the Universe forgive you. Intrusive memories can be managed -- talk to a specialist. Best, think of the GOOD things that await a wiser and kinder you.

Agree W' : Dr Friedlander. Try what he suggests, if you need more help contact a psychologist to figure out what is keeping you focused on the past, so that you can move on into the future.