Any ideas?? -TMI

I BD on the 8th & 9th on ovulation, on the 20th I thought I got AF, but it was never enough to fill a tampon and only lasted 3 days (mine is always heavy and last 6-7). I’ve tested and it’s come out negative. I woke up two days ago to these really sharp cramps that only lasted about a minute or two. & now this? What in the world