Could I be pregnant?

I had unprotected sex on the 9th of September. Six days after - I experienced some bleeding but it wasn't like a normal period. It was slightly heavy for the first day, just some spotting on the second day and gone by the third. I'm not due a period for another week and a half. I have been unusually tired for the last 3 days. I have been feeling pretty bloated and I'm constipated. I felt dizzy when going for a run the other night which isn't normal. Should I take a test next week to be sure?