It is using antifreeze

Antifreeze can only leak out or go out the tailpipe. If there are no external leaks, one would suspect a cracked cylinder head, intake manifold (only on some vehicles) or a bad head gasket. Probably not what you wanted to hear, but it is what it is.

So is the motor still good. Or what do I need to replace

You need to take it to a reputable mechanic and have the cause of the lost coolant properly evaluated. If it has a leaky water pump or some similar problem then it can repaired for a reasonable amount. If the head gasket needs replaced than that is an expensive repair requiring the entire top of the engine to be removed and replaced. I have no way to determine exactly what the problem is sitting behind this keyboard.