A/C possilbly leading to gas leak?

I just bought a 1994 honda civic lx 4 cylinder automatic with 112000 miles in great shape. The A/C was warm so I put in R134a that advertised it was for high mileage cars and had A/C part conditioners in it. Now there is a groggling almost grinding noise coming from maybe the fan and intake system or underneath them. That is only when i am idling or parked and it comes and goes but there is a zippy or a fast clanking noise randomly while I am driving. I am pretty sure that the zippy noises happen in response to acceleration. The scariest part is that when I turn the A/C on my gas meter can go from half full to quarter tank in 15 to 20 minutes. The A/C is not even cold also. I'd appreciate anything...thanks guys!!!