Car overheating

So car is over heating, temperature warning light is regularly on, losing water from somewhere and only takes about 800 mls of water when topping up. Foggy inside when it’s icy outside, making a grinding noise in certain gears, misfiring and low power. No heat inside at all. Tried head gasket sealer although oil looks fine cloudy oil is usually sign of head gasket? Mines not cloudy. Tried changing water pump, tried to get rid of air lock. What else could it be?