The troops at camp are all monstergirls

Well that's new. It would appear that the soldiers stationed in the nearby barracks and armory outside the fortress are all humanoid females.

You watch as the clearly polymorphed figures stagger to their feet and stumble in panic of their new soft, feminine forms. Once poised and deadly lizardmen struggle to keep their armor straight on their slight frames. Former boar-headed Orc Marauders are reduced to pink-skinned, floppy-eared, curly-tailed wenches, waddling up and down and squealing their heads off. A greatly tall, muscled, green-skinned Amazon with the protruding canine-teeth and straight horns of an Ogre swings a gilded axe meant to mark a base officer and roars for order.

It seems that whatever happened to you happened to a lot of other members of the horde, if not all of them. Perhaps you should investigate further?

You turn and look around your lab, half-hoping that the key to the mystery is just lying unattended on one of your desks, though realistically more just wanting some inspiration for how to proceed with the revelation of conspiracy.