Could it be??

Munz
Hi! Hope you're all well!!
Well, We've had sex every night for the past 7 days due to ovulation days. We've been trying for a good few years now and this evening I suddenly had excruciating pain in my pelvic area. Any idea what this could be? An untlrasound was done 7 days ago and there was a follicle around 16mm.. I have some terrible lower back aches