Why is my Mazda overheating, leaking antifreeze or water, leaking oil, no heat

Hello, The coolant/water leak is the cause of overheating and heater failure, though there may be additional issues. Adding coolant is essential here, or you will certainly lose your engine or head gasket. Accelerating without pressing the gas is fine up to maybe 5mph, but if it is really trying to go, you probably have a large vacuum leak. This may be associated to the oil leak. This vehicle needs a professional, maintenance, and a thorough inspection. From the sounds of it, if you don't treat it to service, you will not be driving it much longer.