First off welcome Kristen! And the m/c was not your fault! It happens, as those of us here know way to often. Stressing does not cause m/c, there are studies all over the place that kill that theory. Just like stress does not cause infertility, but infertility causes stress!
The answer tests tend to give long positive periods. I would trust FF and when the O line is darker. Just relax, and have fun with
btw, early m/c's are many times caused by chromosonal problems which can be from the male side.