Soft brake pedal and fluid keeps on coming out of reservoir?

Okay, the brake pedal felt kind of hard and by looking at the rotors I can tell that they needed to be changed. Once the tires were off, I seen somebody had changed the pads that being as I already had them on hand, I changed both them and rotors on all four corners. Once I got around to the back passenger side caliper after removing it, it sprung a leak, so I replaced it. BTW this is four-wheel disc brakes. After installation of said caliper, I bled that corner. Once everything was put back together now, I have a soft brake pedal and fluid keeps on coming out of reservoir. It also did this when pushing caliper Pistons back into place. (Given). Did I screw up the master cylinder with the pressure?