I added coolant and haven't noticed any leaks. I drive 60 miles round trip daily for work and it just started to have these overheating problems in the past few weeks. After turning the heater on full blast the temperature goes back to the normal range and everything seems fine again.
You may have a leak you have not seen if you had to add coolant. You should also not have to turn on the heater to full blast to cool the engine. This tells me you either have a cooling fan that is not working or a radiator that is clogged. I would suggest having a mechanic, such as one from YourMechanic, come to you to diagnose the overheating issue by first pressure testing it for leaks and then checking coolant quality and radiator for proper flow and fan operation.