Very low bbt

Christie • 29 years old. TTC since September 2013.
I have very low bbts ranging from 95.6 - 96.4. I'm off the charts (literally)! I looked it up and everything said hypothyroid. This was super concerning to me so I made an appointment with an endocrinolist and had lab work done. Everything came back normal. No thyroid issues. Does anyone else have low bbt? Does anyone know someone who had low bbt and successfully conceived? My husband and I have been ttc for 6 months. I'm starting to think it's because of my icebox of a uterus. Other info, im 28, active and at a healthy weight. What could be causing my bbt to be so low!? Any ideas??