I'm not sure what to make of that. What made the nurse think you O'd based on your u/s? Was the follicle smaller today? You need a surge to ovulate- whether it is from a trigger or your own body's production of LH. Your LH doesn't seem high enough to surge, but maybe if your LH was really low to start with it could've been a surge- I just don't know- sorry I'm not much help:(
What was your progesterone level today? I think most places say if it's above 3 that's indicative of ovulation.
I hope you get a more definitive answer tomorrow. I know how frustrating this is!!