Pedal that went to the floor and then fixed itself probably mean you lost a brake pad and now you're using the Piston/caliper to stop (it should make grinding noise and your rotor / Piston / caliper won't last long)

I'd get this fixed, if I'm right you're going to lose half the braking power of your car soon. (Pretty much all cars have a dual braking system, if shit happens you lose one front and one rear brake but not everything)