What Causes Nausea And Burning Sensation In Throat Post Intake Of Pizotifen?

Hi, I swallowed a small tablet during the night, half asleep then woke up 5hrs later feeling nauseous and burning sensation in my throat like heartburn.I was sick once soon after. It was one pizotifen I took. Can t remember if I took a drink with it or not. Should I be worried or can I self medicate?