AC/Heat issue

so I am in FL and it got a ittle chilly last night. I turned on the heat. I couldn't get it working right, didn't feel like it was coming up so I played around with it- used a setting called EmHeat and got it going. When it hit 68 degrees, I turned the whole system off. However, the heat kept going (it was a sweaty 76 degrees when I woke up). I tried just running the AC hopefully to override it. It cooled but now that I've shut the system off again, the heat is once again on. Any ideas before I call an AC guy. The unit is electric and runs both heat/cool in same system.

I'm realizing EmHeat probably stood for emergency heat, right? How do I get it off?!?

If you have a model number for the thermostat, try googling to find the owner's/operation manual?