So I just replaced my head gasket on my 97 4 runner v6 and had the heads resurfaced it seemed to be running alright until I would apply my brakes and my oil light would start to flicker and now my car is overheating. The oil is fine and the radiator seems to be fine but why is my car overheating can someone please help I don't want to drive around in 100degree heat blasting my heater but I'm terrified I will blow my head gasket again

 

Did you replace the thermostat? If not, it could be stuck partially open.
Did you change the oil? If not, coolant could have entered the crankcase and diluted / thinned the oil.

 

^ That and possibly your timing is off so the oil light may be coming on because the engine is about to die at stops.