Ovary Pain???

For months I have had random stabbing pain in my ovaries. Some times it’s around ovulation, but not always. I had an ultrasound done back in April and everything was normal. But 2 nights ago, I woke up in the middle of the night with excruciating stabbing pain in my ovaries. It lasted about 30 seconds, then went away. The next morning, I had a shooting pain from the left side of my vagina up to my left ovary. It happened again today. I am 1 week away from my period. Any thoughts on why this is happening?