Pain during sex

On July 6th, I had sex. About a minute or so before we finished, I got a horrible cramp-like feeling. The feeling was around the uterus area. The pain was so bad I thought I was going to throw up and it was hard to move. I jumped into the bath, turned on the hot water and soaked. The pin lasted less than 5 min. I didn't think anything of it but I just got done having sex and it was the same exact thing. The pain is horrible. Honestly feels like it is between extreme period cramps and a light contraction. Anyone know what this could be? The pain is only during that time. After, it is completely gone.

*calling doctor later today