2003 Volkswagen Passat slumping brake pedal

I changed rear brake pads on our Passat. It's all together again. I can lift the brake pedal up with my foot, but when I let it go the brake pedal slumps about 1 inch and the brake lights go on and stay on. The brakes also apply themselves, so I can only drive the car by holding up the pedal.

Thanks,

Tom