Someone please ease my mind!

I had unprotected sex 3 days before I started my cycle. My boyfriend ejaculated inside of me but my period came as usual with nothing out of the ordinary. I am due to start my period again on Febuary 3rd but the last couple of weeks I have had a hazy feeling and just felt very weak, lightheaded and dizzy. I didn't think it was possible to get pregnant that close to your period? I took a test last week to ease my mind and it was negative. I still have the hazy/dizziness though. Am I being dramatic or could I be pregnant? No other signs or symptoms.