What Causes Pain And Pressure In Vagina And Rectum After Having Sex?

I am a 40 year old woman who was single for a long time. I had sex with my boyfriend for the 4th time. it was also unprotected, unlike the first 3 times. he is very large and i am very small, i had a slight pink discharge right afterwards (i am thinking blood) it is 3 days later and i am feeling major pressure and pains in the vaginal, rectum area. i am very tender to the touch and to pee/wipe in the opening of my vagina. also the skin on my bottom and inner thighs is very sensitive to the touch which makes sitting and walking very uncomfortable. i used a mirror and there is no visible signs of cuts, bumps, rashes or sores of any kind and the coloring is normal..there is also no discharge or odors. why am i feeling the pain and pressure?????? and what can i do to get relief since a hot bath did not help.. i am going to get checked tomorrow morning for everything and anything related to STI's..... i apologize as i did not realize i had to pay.. i do not have the funds at this time.