i have a N/A 87 rx7 and since yesterday i felt my brakes were acting wierd, but today when i was about to leave i felt as if i have no brakes and there is a "STOP" light that goes on everytime i press the brake pedal, the brake pedal also goes all the way down to the floor when i press it. but it comes all the way up when i let go.

can anybody help with whats wrong??