i think i'm pregnant, i'm having strange symptoms

I had unprotected sex on April 29/07 and May 3/07. My period started on May 15/07. During my period I had hot flashes (which I don't usually have) also a little nauseous. This week I've been quite nauseous,hot flashes, lower abdomen pain, some pulling sensation on the left side of my waist, some lower back pain as well, and wooziness as well. I did take a pregnancy test on the May 20/07, it was negative. Could I still be pregnant. I just feel that I may be. I'm also urinating quite often.

I have all those symptoms and I'm getting tested for a cyst on my ovary.. does it hurt when you have sex too?