A few questions to clarify your situation: 1. Is the room on the side of the house that is hit by prevailing winds? 2. Is it served by the central systme. 3. Is there a return air outlet? 4. Is it the furtherest room from the central systme?
No, the insulation doesn't deteriorate as rule, as long as it stays dry. However, some blown in insulation will settle in the walls but we're talking something like 6" from the ceiling. That shouldn't cause your problem.
Welcome to our little group; we are all anxious to help and we like pictures too.