Exciting opk

Whitney • Proud mom of 3 year old baby girl and baby boy due in December.
There are 2 test on the cd15 and cd16. I think it's safe to say I had a surge on cd16. Had cramping and all opk on cd16 (I took like 5) were this dark. Can I just get some reassurance. Also we bd'ed cd14 and cd16, we will probably bd on cd 18 too just to make sure. It couldn't harm anything right????