My husband and I had protected sex yesterday morning and after we finished I went to the bathroom to pee and found that I was bleeding (bright red) and now I have had slight bleeding all day yesterday as well as light lower back pain, a little dizziness, a little nausea and light cramping, I have only needed one pad yesterday, I generally have irregular periods that usually come anywhere from 23-26 days from the last period, and are generally heavy, my last one started April 10th. I just want to know could I be pregnant or could this jus be my period and itironically started after having sex or could this be serious.