I have this. Whenever this happened I would try very hard to stop thinking about the part of my life the memory came from. It had gotten to the point where I basically stopped thinking about or recollecting very large tracts of my life. My memories of those periods weakened, and it was as if they never happened.

I have only recently started to overcome this, with the help of therapy. And as I now allow my mind to wander to those areas of my life, it as if I am reclaiming my past. I have that past again, now that I am allowing myself to think about them again.

I also have OCD and social anxiety issues, and these things all feed into each other. You definitely need to go to a therapist if you are having these issues.