I have a bryant thermostat that when I set it to 75 it kicks off at 70 and the aux heat comes on and the temperature starts dropping and it gets very cold in here. I don't have a manual to know how to program to stay at 75 or to kick in when it drops below. I hope you can help me I put it on hold but it doesn't seem to be doing any good and I don't know what e-heat or auto means under the mode button.

If the thermostat has an E-heat you must have a heat pump. If you have just switched the thermostat the wiring could be wrong.