Spongy feeling on brake pedal.

My brakes have grown extreme soft and weak within the last month. They feel as if they are being over worked. When I am backing out of my driveway on a slight decline it almost seems like they don't even work. I have discs in the front and drums in the back. I have to start braking extremely early to ensure I stop in time. Even when brake pedal is fully depressed, it still doesn't stop, just slow lurks to a halt.