What could this be? Please Help with some insight..

[JaneDoe21]

Ok so a few days ago (3) I was having intercourse with my boyfriend, when all of a sudden I have this Horribly intense pain in my lower left abdomen, It was so bad that I had to stop. Now three days later the pain is still there... it hurts when I sit down, and the spot is very tender. Although it is an ongoing pain, it hurts alot, and the pain like i said hurts when i sit down and sparatically through out the day. I dont know ehat this ccould possibly be. I should be getting my period around the 5th or 6th. I mentiuon this because I have been nausous for the past 4 days for no reason, and its all day long, when i wake up, in the middle of the day, after i eat at night.. Like the pain the nausea comes and goes all day long, I havent been throwing up but its almost gotten to that point. I have been having unprotected sex for the past month. Is there anyway I am pregnant, i really dont know what is going on with my body, and I am very worried about this. Im thinking it could be a cyst, or somethign.. Someone please help. thanks so much!