It can be very frustrating, but that's likely the new medicine messing with her gut. She's still willing to eat, even if she is eating less. I also would not fret the minor weight loss. A single poo can be grams worth.
I made a pledge to Richter, my male, that the day he declines a super worm, his favorite, favorite food, is the day I would be worried. While he was being medicated for coccidia, he turned his head and closed his eyes at a super. I cried.
I immediately ordered the reptiphilus that day, and the day after having some, he started accepting food again, but in the meanwhile he went days without eating as it shipped