She could have a hairball that's blocking her digestive system. If so, she could need immediate attention. It's ahrd to say with kittys, because they like to hide the symptoms as much as possible. The medication might be causing her to throw up, you could look the medication up online and see if there's anything about it causing vomiting.
Check constantly to see if she's becoming dehydrated, if she is, you may need a emergency vet visit for fluids. Cats can become dehydrated fast, and it can destroy their kidneys.
Good luck, I'll think some good thoughts for kitty to get better.