Low BBT

Maggie • Age 29. Baby #1 on the way!
I just had an early miscarriage, and I decided to start charting BBTs again, as I'd like to start TTC soon. Before my m/c, my early cycle temps were in the low 97s. Now, my temps are in the 96s, and this morning it was 96.4. Has anyone else experienced this? Is this something I need to worry about? What temp is considered "too low?"