Well, I didn't take my own advice and I tested last night and this morning with FRER. I don't like what I'm seeing, and now I'm more worried than ever.
Here's all of the FRER I've taken. The line is darkest at 15dpo, and I'm pretty sure my last two are getting lighter. The line should surely be much darker at 19dpo today. My dollar store test is significantly lighter with today's FMU since yesterdays middle of the day test. Any encouraging words? If this is what I think it is, when will I know?
https://i45.tinypic.com/3479q38.jpg