Unprotected Sex two days after period, feeling dizzy, nauseous, and have extremely sore breast.

Hi I am a healthy 27 year old, with normal periods. My period began on Nov. 22nd and ended Nov. 26th. On Nov. 28th I had unprotected sex, using the withdrawl method 3 times. I know this is not full proof, but I didn't think I would be fertile yet. Well a week after that I had experienced nausea, lightheadedness, and faint. My breast were also extremely tender. The thought of pregnancy came to my mind, but I kind of disregarded it, until I would start to feel extremely nauseous at times, or dizzy, because I have never experience this before my period ever!!! Right now I don't know what to think, because I have friends and family that keep telling me they think I'm pregnant because of my symptoms. I'm not trying to stress out about it, because I just prefer to wait and see if my period comes on Nov. 19th. I just need other people's feedback and thoughts on my situation. Thanks