Need help with kitty

[Aespinel]

Hi everyone I just googled and found this website and I wanted to see if someone can help me with this. I have a cat named Mona and she has mild flea allergies. Every winter we get fleas and we treat everyone in the house. Last week I noticed that she got bit and now has a scab on her neck. We took her to the vet today and she was prescribed Clavamox (1 mL) and Prednisone (5 mg). I gave her both as the doctor prescribed at noon and at five she threw up clear foamy bile. About an hour later, she threw up twice again. She stopped since then however I'm afraid to give her the medicine again. I called the afterhours number for my vet but they won't return my call so I decided to call the pet hospital at Texas A&M and they suggested I take her off the clavamox until tomorrow since my vet opens at two. They told me however to keep giving her the Prednisone and see if she throws up again. I'm not sure if I want to do that since I don't want her throwing up again. What should I do??? Thank you all for reading this and your future suggestions!!