on friday my boyfriend and had sex and afterwards i had a very severe pain on the left side of my lower back. then saturday we did it again the pain came back but i also felt a pain in my lower stomach and in my vagina just where my pubic hair begins and it was so severe that i could not get up and walk. when i could move i colud urinate. also after sex wth him i always feel nausea. why is going on ?

Optional Information:
Female , Age: 23

Already Tried:
nothing this was the first time