Must I make up the prayers of three days that I had previously intended to repeat due to the emission of semen, even though I now doubt that occurred?

Praise be to Allah, who has cured you of the whispers (waswasah). To get rid of them, you must ignore them and not pay them any attention. As long as you are in doubt about the emission of semen, you are not required to make up the prayers, because the original principle is your innocence, and there is no certainty to the contrary. We advise you not to dwell on these whispers and to completely turn away from them until you fully recover.