If you have 28 day cycles you would ovulate (well normally) around the 14th day of your cycle. I would say you are not pregnant yet however his sperm can live in you for up to 5 days so you could get pregnant depending on when you ovulate. You may just have a stretched stomach muscle - I would say you are not pregnant.

I think you mean can you get symptoms of pregnancy that fast. Or at least I hope so becuase if you dont know that you can get pregnant from having sex 4 times then you shouldnt be having it. Anywho, I think its mostly all in your head. I didnt get any symptoms of being pregnant untill a couple days before I was supposed to miss my period and even then stomach pains wasnt one of them, I had cramps not pains. My advice to you is take a test only if you miss your next period. Its pointless to take one now. Also just out of curosity are you trying to get pregnant?

I wouldn't be worried so much about being pregnant right now, but having unprotected sex repeatedly will certainly encourage a pregnancy. It also encourages the spread of std's. It's not the wisest thing to do if you're not completely prepared to handle the consequences. You should consider using protection in the future, and if you miss your next period, definitely take a pregnancy test. Stay safe, hon.