So every OPK I've taken since has been lighter and lighter (with a surprisingly clear progression). And last night I had some pink spotting. I'm a bit worried I actually MISSED the surge already! Ultrasound this morning showed a 16 mm follie, which is probably on the small side to have ovulated already, but the blood work will tell them for sure what's going on.
The follie is on my left side (with the endometrioma) which is not the side I usually ovulate from, so it's possible things just seem a little weird because of that.