Q: I use a lot of antifreeze like 2 gallons a week

This suggests that your engine is either leaking the anti-freeze out of the cooling system or you may have a blown cylinder head gasket. In the case of a leak, this will be noticeable by the coolant being leaked out onto the ground from either leaking hoses, the coolant overflow tank or possibly from the water pump. In the case of a blown head gasket, the gasket between the cylinder head and the engine block is damaged (often times as a result of overheating), causing the coolant to be leaked into the cylinders. When this happens, the coolant is burned along with the fuel which results going through coolant very quickly as you describe. These two possibilities are very different in terms of the repairs needed and the cost to fix. I would suggest having an expert from YourMechanic come to your location to take a look at your vehicle to determine what is causing the overheating.