Ovulation spotting ?

So today I’m on cycle day 15 and got a positive smiley face on my clear blue opk and notice small amount blood after sex. So hubby and I did indeed bd. But prior to today on cycle day 13-14 I notice spotting as well not much but it was there. I took an ovulation test on the 14th but it was negative . Also should I Add a few days after af which I believe was cycle day 8 , me and my husband bd that day too. I know it’s too soon to be implantation and this is my first time using a opk and we’ve been ttc for 6months now and really want to conceive !!