Blood after sex

Katie • Stay at home mommy as of 6/30/16!!!
My period ended th 2/26 and tonight after sex I layed flat for about 5 mins then went to wipe up and had bleeding. Not much spotting amt. Never happened before. 
Is it just old blood trying to escape? Or ovulation blood? Sometimes I spot while ovulating. Hmmmmm I hope it's nothing major as we are back at month 7 trying for that baby!!!
Any ideas...does it happen to you?