You obviously have a coolant leak somewhere in the cooling system. The fact that you noticed a coolant leak and continued driving it home without filling the system with coolant or repairing the leak first, you may have caused a blown head gasket driving it home. I would re4comend filling it with coolant and permit it to purge while filling it. Wait about 15 minutes or so after filling and see if the coolant level goes down as the airlock passes). After you have filled the system and sure it is full without an airlock; replace the cap and crank the car. See if any coolant is coming out the tailpipe as it idles or is revved up. Look for coolant leaks in the rubber hoses to the radiator, the radiator itself, and heater hoses on the firewall. Keep an eye on the temperature to see if it is overheating as you are checking things out. Driving it with low to no coolant was not what should have been done and you may have caused some serious damage to the engine.