This just started a couple of days ago. I checked everything. My fan works, nothing leaks. So the only thing it could be is the thermostat. Another thing is that today, when i was at a red light the car over heats but when im driving it goes back to normal. This is the first time it ever has done that. What else could it be besides the thermostat?

 

It's the thermostat. My car did that twice so now I change it at least once a year. Turn on the heat and run your defroster on full and it will help draw heat out of the enigne until you can get the thermostat changed. This is quick and easy, shouldn't take you more than 20 minutes to fix.