What exactly are you feeding her each night?
Meal Worms are not a good source of protein - they are mostly fat.
Your glider needs to be on a well balanced feeding plan if you expect her to successfully nurse healthy growing joeys.
If you are not following one of the widely used glider diets you may want to get your gliders on a good diet ASAP.
If you think your gliders may be having diarrhea - a vet visit for both is the next step. Fecal testing needs to be done to make sure they do not have any parasites that can cause many other health issues including diarrhea.
Not grooming can also be a sign of illness.