I once had a doctor who had told me that; I have an ability that many people don't have (That my mind has the ability to could go back..?

I am not sure what he was talking about, what can go back, it is possible in some rare cases for someone who is not ill, that is just anyone to have an ability where they can go back in time in their minds and remember things in great detail that other people do not have the ability to do, it can be done in various ways that only you can do for instance you can remember remarkable details by thinking of an incident as a tree, the main thing as the trunk, the worth it stuff as the branches, the details start with the twigs and leaves and finally the berries.
many people indeed do not have it, it is remarkably rare i am not sure if it can be harnessed under illness. you need to find your own way to do it. my maternal grandmother and her son, my maternal uncle had it.
You can travel back to the situation like it was real, even if you at the time do not think you will ever go back there, you are one of the few, i have never come across it before.
yes he was a credible person, also it can be done with other ability, my uncle did not read as others did, he just turned over the pages and could repeat a single paragraph from anywhere in the papers, travel back goes with that ability it is unusual but does exist.

Just because someone is a doctor does not mean that they are not also an idiot.

He is not a credible person.