Head gaskets leaking and gas odor after filling tank

If your Headgasket is leaking it may be Coolant, you need to replace your hardgasket there's now way to alternate that situation ! For the gas odor, check if there's any leak, fullfil your car at a gas station park it and check under of it an hour later to see if there's leak spot on the ground, if there's check where it is wet, if it's a line or the tank !? If there's not any leak, maybe a bad Fuel Pump cover gasket, or Evap System not working properly, or your Fuel Cap is not seating properly due to a dried seal !