Just doing a quick pop-in

Okay, What I'm assuming is that they saw the LH level at 20.5 and the dropping E2 and believe you were ovulating. especially since the follicle disappeared. Typically, your P4 will start rising while you are ovulating and you'd see a P4 around 1-3 at that point before it rises more. BUT, there could be a slight delay in the P4 going up. I would have checked P4 the next day or so to verify that the P4 was going up. But that is just my opinion. I think the odds are actually decent (about 75 percent) that you were ovulating based on that LH level and your E2 dropping and the size of the follie. (But it would be helpful to have the LH levels leading up that day just for more clarity.)

I'm a little surprised they didn't have you do a follow-up P4 on Saturday, though. But it is possible that something was noted in the u/s reports that they considered as well (such as echoes in the follicle right before it disappeared, etc.)

At this point, without any additional b/w, I'd lean towards taking the P4 and E2. But, if you haven't started the P4 and estrace and you want to be absolutely certain, you could still ask to do a P4 test tomorrow. If you have started the P4 and Estrace, then I'd continue them and figure that they will at least mimic a normal post-ovulation phase and help you have a good start to your next cycle.

If I get a chance later, I'll check my notes and see if I have any examples of cycles where my P4 rose slowly. I know typically I could see a pattern, but occasionally there were oddities thrown in there (just to make me nuts!).