loose stools after surgery--longish

Sunny was spayed a week ago from yesterday and also had an umbilical hernia repaired. She took rimadyl for 2 days afterwards and I noticed her stools were loose and attributed it to that. But now she has had no pain medication for 5 days and she continues to have loose stools. This is not diarrhea. She has not had an accident so holding it is not an issue. She is going twice a day and making a small volume of stinky loose lighter colored than usual stool--I always pick up after her so I know they are loose and smellier than usual. She is on interceptor for HW/worm prevention so I am not worried about intestinal worms and I have not seen any worm parts in her stool. Her appetite for people food is intact but she is much pickier than usual with dry food. Either me or my fiance has to encourage her to eat her dry food by sitting with her and feeding it to her and now that is barely working. We go back to the vet on Saturday for stitches to be removed. We already had on trip to the vet 2 days ago b/c she limped a few times and I was paranoid; her incisions look great according to the vet. They look the same as they did 2 days ago to me so I know infection is not an issue. Before I get back to the vet does anyone have any ideas about the change in stools and low appetite? I should also mention I know she is capable of eating a normal amount b/c I mixed canned with dry for a few days after her surgery. Also, fleas are a real problem and even with using frontline plus every 2 weeks I am still seeing fleas so I am worried tapeworm is a possibility. Thanks in advance for any advice!