I don't think this is specific to roller hockey -- your'e not banished to here just because you're on wheels.
I've played in a few tournaments -- once my team was schedule for three games in one day! These were on ice, so I was probably cooler than you, but I still tend to sweat like a pig when I play. So I make sure to keep well hydrated while I play. In an hour and a half of pickup hockey, I go through about a quart of half-and-half Gatorade and water.
How much water were you drinking during your game? Were you allowed to keep a water bottle on the net?