TTC month 9

My wife and I have been trying to conceive for 8 months now, and got our hopes really high this month when she was feeling crazy irritable, extra exhausted, and more tearful than usual for her. Her period was 3 days late, but we kept getting negative pregnancy tests. Finally, I called the doctor to ask if we could get a blood test to verify definitively, and less than ten minutes later, she got her period. No cramps, no warning, Just bright red blood. Typically her cramps are unbearably bad-- and she has brown discharge for several hours if not a full day before the red period starts. Has this happened to anyone else? She's NEVER been late in the 8 months we've been trying, and I'm just curious if it's at all possible this was a chemical pregnancy that couldn't be sustained due to low progesterone?