Q: Brake pressure low and brakes growling

Sounds like you brake pads are down to the metal. Brake pads have a metal backing plate, but the part that actually contacts with the rotor to stop your vehicle is a friction lining usually made up of an organic material and some soft metallic fibers. When this lining wears out totally, the metal backing plate makes contact with the rotor causing a grinding noise like what you are hearing. The part that squeezes your pads onto the rotor is called a caliper. The caliper has a piston that is hydraulically driven when you step on the pedal. As the pads wear, the caliper requires more fluid to take up the space of the worn pads. This will cause a low fluid condition on the master cylinder turning your light on and the worn brake pads cause the low pedal feel. By now, I suspect there is damage to the rotors as well as a possibility that the caliper might be leaking. A complete brake inspection is necessary to see exactly what is damaged and what needs replacing.