Could be implantation bleeding.. give it a week..
And my period is usually spot on for starting on the day it's suppose too.
I was due to ovulated the 30th of July and I had sex the 28th, 31st, and 4th of August and I usually have a 30 day cycle. I took one this past weekend but negative. I didn't find our with my daughter till I was 4 1/2 months.
I had a dark brown discharge. I knew immediately I was because my periods are never that way.
You could be, I had pink discharge at the beginning of my pregnancy, you should take a pregnancy test asap