Well sometimes it is an uphill task, to forget the past, but there are ways that can make this difficult time a bit easy like,
->keep busy yourself in some kind of work that interests you.
->don't dare to be alone, because it's when a guilty feeling comes to the mind, and can turn out behavior after it can be dangerous.
->meet your friends, ask them if a situation seems really hard to let go off.
->Think about present because it's what we fully possess and not past that is lost but the future that depends on this moment.
SO, this is how i do it:)