You definitely have some symptoms that don't sound all that great. The fact that coolant is disappering rather quickly, and is not leaking, pretty much confirms that you have an issue with the head gasket or the head itself. It's really impossible to know the culprit until the head comes off and is examined carefully. However, the odds favor the cracked head, based upon the results of members here.

You can't continue to drive it forever in this condition. The constant input of coolant into the combustion chamber is only going to get worse.

If you can spend the time to learn the engine and do the labor yourself, then consider keeping the vehicle. Otherwise, sell it.