What Causes Severe Pain In Lower Abdomen After The Intercourse?

After intercourse I had a really bad pain in my lower abdomen & I couldn t take the pain I had to ball up like a ball & I also threw up. This doesn t happen very often I ve been with my boyfriend for 3 years now & out of the 3 years I ve had this issue at least 2 times one Time last year & one time this year. Do u know what that can be?