Nausea More Condition_symptoms Why Am I Feeling Nausea During Sex And Even More When I Climax?

Why am i feeling nausea during sex and even more when i climax? - nausea more condition_symptoms

Sometimes when I'm having sex with my boyfriend when he reached the climax i sometimes begin to feel sick, and sometimes I feel that I am punished so badly that we need to stop. then the disease takes about 20 minutes.
Others have asked this question, but nobody gives a reasonable answer.

Note:
- I am not pregnant
- I am very attracted to my friend
- I'm not nervous
- I do not think so, pain during sex

Thank you!