98 Sunfire Brake pedal hits the floor

Hi, yesterday I started up my car (pushed in the clutch and brake everything felt normal) then when I lifted the e-brake my brake foot immediately hit the floor with no resistance. I do have some brakes as long as my foot is holding the pedal all the way down but like I said there is no resistance and there is no braking until the pedal hits the floor.

We checked the brake fluid and there's plenty. Also when the car is off the pedal hits the floor just like it does when it's on. We're thinking it could be the brake master cylinder or the brake booster.

Thanks.