Yesterday I noticed my 4 indoor cats have fleas. I went to petsmart & purchased them all flea collars & a 3 month supply of some type of medicine you put between the shoulder blades. I used a 1 month supply tube on 2 of my cats and split the third tube between the two smallest. That night I put the flea collars on them as well. This morning after eating breakfast, my youngest cat (5 months old, the medicine said its safe for 12 weeks&older) went diarrehea on the floor in my kitchen. I’m worried it could be a side effect to the medicine so I took off all their flea collars. She has been acting normal since (eating and playing) but I am still very concerned. Do you think I should take her to the vet or wait it out?