I had the same problem yesterday. I use a 6 gallon glass carboy so I know it wasn't the squeezing that caused the drop in levels in the airlock. I guess it was just maybe the cooling that was taking place. This time I used vodka as the liquid instead of water. It is slowly bubbling away...
I made my first batch this weekend and jumped in feet first with 5 gallons too. I took one of the simplest recipes I could find; 5 gallons cider with no preservatives, 5 lbs sugar and I used Lalvin D47 yeast. It is doing a slow bubble in the carboy and when I get close enough to it I can...