Your question might have been written by me. I frequently find myself experiencing memories of mistakes I made in my past (none of any real significance) and the emotions that accompanied them. Since I am just short of being eighty-one, there are many. Of course, when I was your age ADD and ADHD were not recognized.
I’m sorry your mother does not understand that you do not choose to have these thoughts and feelings, which are not ridiculous, but I am not surprised. Only people who have problems like these can fully empathize. The same thing is true for those suffering from PTSD, whether their trauma is from war experiences or childhood trauma (which I have).
I think some people are especially sensitive and feel their emotions more strongly than most do. I know I am one. We feel the need to be at least accepted by others, if not actually liked. It seems no matter how hard we try we feel like we have failed. Somehow, though we have friends including one or two close ones we still feel as though we were outcasts (at least this was true for me).
When I was twenty, someone told me that despite my intelligence I lacked common sense. I struggled for many years trying to understand what common sense was so I could acquire it. Common sense is the ability to automatically understand what everyone else understands even when the context is obscure. Clearly, this was something one either has or does not. I discussed this with a friend who happened to be a psychiatrist. He said that I had uncommon sense. It’s true. I see things from a perspective different from most. It is actually a gift. I suspect you have this gift as well.
While I wish I could tell you how to stop the unwanted recollections from arising, but given the fact that mine still happens multiple times a day, it’s obvious I don’t have a clue how to accomplish this. On second thought, if this mental activity is a byproduct of uncommon sense then I am willing to live with it rather than lose my unique perspectives. I think that I survived the frustration, anger, and depression that being different produces by learning to not fight it but instead to embrace it. It is who I am, and I have learned to like who I am. I hope you can too.