Spotting -- help!

I ovulated Sunday, and during my fertile window last week i had some spotting after sex (which is sorta normal for me). However the last 2 days it's been heavier spotting, especially today - in 2 hours I've had to change my panty liner twice so it's more than just a little spotting throughout the day. No clots, no cramps. Saturday and Sunday my right side hurt but I attributed that to ovulation. Period isn't supposed to start until the 27 or 28. Thoughts? Anyone else have post ovulation  bleeding or  random heavy spotting?