I agree with addysmama. Frequent vomiting can easily irritate your throat. You may need some intravenous fluids though just from not being able to keep much if anything down. Maybe some meds such as zofran or phenergan as well. Hope it passes soon
If its bright red and isn't the only thing you are vomiting, then your throat is probably just irritated. If it is dark and looks like coffee grounds then go to the hospital asap.