Should I give my cat another worm pill?

Should I give my cat another worm pill dosage if she throws it up? We gave her a half of a worm pill as the vet prescribed (she is about 2 years old and is around 12lbs). Within 45min to 1hr of ingesting the dose, she threw up about 3x more than she normally does. This vomit consisted of food, worms, and the pill. About 1.5hours after ingestion she still shows signs of having worms as she is still gagging as if they are in her throat. Should I give her another dose of the pill (1/2 of a pill)?