There is no way to determine where the abbreviation BBT (most commonly, Be Back Tomorrow in texting lingo) originated from, or who created it. It will just remain an enduring language mystery.

what is bbt bank code

You can do online banking at BBT by enrolling in BBT online banking. Once you have enrolled, you can login to the BBT website and pay bills or check transfers online.

The day after you will see an increase in BBT to a minimum of .2 above the coverline, and the BBT will stay that high for at least a few days straight.

It is possible that your BBT did increase but the thermometer had a mis-read. You would need to have an increase in BBT to show that you ovulated, and you need to ovulate to get pregnant, and then the BBT needs to stay high to sustain a pregnancy. The increase doesn't have to be much (as small as .2 above the coverline can be considered, I believe).