What Causes Heavy Bleeding From My Vagina And Vomiting After Having Sex?

Ive been having sex with my partner for 11 month now we have never had Any problems up until now when we finished having sex we noticed alot of blood all over the bed and ourselves it was literally dripping from us. I had cramp in my tummy after but nothing major. Im on the pill also. A few nights later we did it again and there was more blood. Each time this has happened i ve vomited. Have you any ideas please?