What Causes Short Periods, Heartburn And Nausea Post Unprotected Sex?

I had unprotected sex about 2 weeks ago on the 12th, my period came on the 23rd but only lasted 2 days, off & on. My periods are usually 4-5 days & they are usually heavy. My cycle is 30-32 days. I have been having headaches,heartburn, abdominal pain,sensitive to smell, I feel nauseous but no vomiting, I get super tired especially after a long day from work. My last cycle was 32 days, my period last month was on the 25th of May. Which last for 4 days with a heavy flow. Could I be pregnant?