What should I do if I forget whether I made up the missed days of Ramadan from menstruation or not, remembering that I fasted immediately after Ramadan, but I am unsure of the exact timing of that?

If you are unsure about making up the days you missed fasting, then you must make them up, because the original ruling is that the debt remains. If you were unaware of the obligation to make up the fasts before the next Ramadan began, then no expiation (kaffarah) is due from you. However, if you wish to be cautious, then feed one poor person for each day, in addition to making up the fast.