last night I was driving and usually my heat bar only goes up three notches...but for some reason last night it went all the way to the end...

so I turned everything off and drove to wher eI needed to get and it started to go back down...

but when I drove home it went up when I turned on the heater....

is this normal???

 

This is not normal it sounds like you are having some cooling issues. Check your parking spots for coolant leaks and your radiator for coolant level. You could have cracked a tube and lost coolant or your thermostat maybe stuck, waterpump dead (unlikely).

Either way it shouldnt be happening. If you drive on the highway the air alone should keep the car temp drivable. Let the car idle until it gets warm watch the temp gauge closely when it gets to 4 let the car cool off and then highway drive it to your mechanic or into your garage to fix. If it doesnt happen again your thermostat probably was just acting up. But you should wary of it happening again in the future.