It snowed here yeasterday and when trying to come to a stop in my driveway the truck started to slide and the antilock brakes kicked in. The truck wasn't stopping so I lifted off the brake and hit them again. As soon as I hit the brakes the pedal went to the floor and the truck finally slid to a stop. Since it was snowy, icy windy I left the truck there until this morning. Started it and pumped the brakes. They went to the floor at first and started to build pressure as I pumped. I then noticed the "brake" light on the dash was on. Pedal again just went to the floor. Any ideas on what could cause this? ABS sensor problem, brake booster failure....not sure where to start, help me out.