Yes I have this problem as well. Of course I'm not getting old... I am old. I get the kinds of flashes you describe all the time. Sometimes I'll have one & I'll suddenly realize what just flashed through my mind happened 40 or even 50 years ago! So why on god's earth am I wincing at it now?

I'm actually losing a lot of my "history" at this point. This is one of the reasons I doubt being in therapy would really be of a lot of help at this point. I can no longer recall enough of my life to really be able to put together an accurate picture of what happened over the years. I just mostly have these random flashes primarily related to embarrassments I suffered or things I regret.
In my case, I approach them with compassionate abiding. It helps...