Has anyone had any issues with this brand?? I bought it and started using it at the beginning of this cycle, but the temps were reading extremely low, 96.1-96.9 F. At first I thought maybe the battery was old, so I switched it out and temps were a little higher 96.8-97.1 at the most. Then I started to use 2 other “regular” thermometers to cross check it. The regular ones would both say 97.3, and my stupid BBT would say 96.77!!! Um that’s a huuuuge difference!! And it did this for several days!! All this time I was thinking something was wrong with me, and it turns out, it’s probably just a crappy BBT!! So mad. 😡😡😡