Sick during sex

My fiancé was going down on me when all of a sudden my stomach started churning.. I thought nothing of it and ended up getting on top of him. Then in the middle of sex (which was feeling amazing) I just started feeling as if I could throw up...almost an hour later I still feel that way. I'm 7 days from my period. Idk what's up or if this is a normal symptom of PMS. I don't believe I've ever had it before or if I did I didn't realize it was PMS. Sorry if any of this was TMI but I was just curious!