These thoughts came up which I pass on, hoping that if it cannot help you along it might will spark thoughts in others.

One: if you were starved for outlet of sub feelings before, it can sometimes happen that you take on too much, and that when you are satiated, or at least have caught up with yourself, you find that you need less, or other, than what you originally embarked on. Too much of something BDSM will pull the brakes in your mind.

Two: As a switch, what used to happen was that when I had had a lot of one side, the other would emerge and demand attention. Could it be something like that?

Third: Do you have any health- or other problems at the moment? Such things can push any Ds back to the background of one's mind automatically - probably a sort of safety mechanism.

Lastly: hope you find your answer, but I'd like to say, if I may, that if it is really gone, you cannot do anything about it, as you cannot give what you do not have, no matter who much you might want to.
On the other hand, it would seem that one does not often simply loose it, though there can be periods where it disappears for one reason or other. I have never heard of that happening, though I have heard of people actively trying to get rid of it for their own reasons.

Good luck.