Thanks again everyone. I'm actually feeling much better. The information sheet that I received with this medication said that in the first 3 days I might experience some side effects but that they should go away when my body becomes used to the medication. I think that my stomach has finally calmed down.

I called Starr's vet and told them about his problem and they said to stop giving him his medicine. Hopefully this will help because he normally has a sensitive stomach and sometimes will have runny poos and diarrhea. I hope that tomorrow is a better day for both of us.