IS THIS NORMAL?

92 190E 2.6, Driving along at 70 mph, I raised the windows and switched on the A/C. It was as if the car went into a lower gear when the compressor engaged and I could actually feel the load on the engine so I switched it back off. No squealing belts or unusual noises. System was just recharged. A/C was unused since last summer, last checked in April was blowing cool... also noticed,...... After last weeks recharge, air from vents was a damp cold, now feels drier, not as cold There is a freon leak somewhere, but what else should I be looking for?