when the compressor runs it pushes freon through tubing in your fridge and the freon frosts the coils which is where the cooling comes from - every 8 or so hours the fridge will go into 'defrost' to melt that frost away so it doesnt turn into a giant chunk of ice back there. that water goes down a small dime sized drain and drains into a pan near the compressor and the heat from the compressor evaporates it away so you never see it. most likely your dime sized drain got clogged by a pea or some other small object and froze over so that the water is overflowing into your fridge because of it. you'll need toremove the screws in your freezer and remove the back wall and you will probably see some ice near the bottom under the metal tubing. you want to melt that ice and find the small drain and use a turkey baster and some hot water to clear it out (you will hear it when its cleared)