Bbt temp was super low

I was supposed to ovulate on Sunday and I’ve been using opk sticks but they haven’t been getting darker. My temp this morning was 97.18 and it’s never been this low before my temp pre ovulation aren’t typically low like it has been. I don’t know what’s going on. I just really want to ovulate this month..next month we are supposed to start iui so I wanted to try one last time naturally before we did iui.

I did had an hsg last month and I’ve read sometimes it can throw your cycle off. Has anyone ever experienced this before???