you need to deal with the memories/thoughts you have of your past. was it a trauma you are remembering? is it a bad experience/bad experiences.

sometimes our mind can make us think of something because you are now ready to deal with it. it is usually a bad memory or experience. talking about them will help it stop. but dont be scared of them, memories cannot hurt you. you have survived the actual events, so memories of it will be harmless.

i am sure our minds know when we are strong enough to confront things from our past, so we just need to embrace them and deal with them accordingly.

hope that helps

simon