95 Accord EXL 4dr 4cyl 185K

Recently, I replaced my rear brake pads (worn out) and bled me entire brake system. I used Honda OE Dot 3 brake fluid and bled all four corners until new, clear fluid was coming through.

After the bleeding, my pedal never felt firm and actually gradually goes to the floor once the car (fluid) gets hot. If I don't continue to press the brake pedal as is goes in, my car will move forward. Sometimes it seems to bottom out.

Surely, the master cylinder or brake booster just didn't up and go bad out of the blue? It seems a little coinsidental after the brake bleed.

Any ideas?

Thanks.