Has anybody had this?

Okay so I have been having these period like cramps for two and a half weeks.. I do have unprotected I had as soon has I got of with no condom. My hurt like three days after I had and I also had sex like three different times after I got off and my next period is in nine days..suppose too. But I have had this weird low andomial pain in my lower left side for those two and a half weeks.. my s feel bigger and my look bigger to me. I only weigh 99 lbs. I have been bloated more hungry than normal considering I never really ate much, I have had more headaches like everyday.. im just wondering what this could be? I do not have stds and neither does my partner.