I had anal sex and now have bad nausea. is this normal, or did i get injured in the process? there has been no bleeding or vomiting as of yet.

Prob no injury: Anal sex may cause fissures which typically show up as pain and bleeding with bms so without these you are probably ok. Nausea is non-specific and probably unrelated, although if it continues, get checked. There is a remote risk of perforation, although very unlikely unless foreign bodies (eg. Sex toys) were involved. Std is also a risk, so see your healthcare provider if symptoms occur!