@gemini
It seems that your AC system is choke. When you serviced your car ac?
Don't run the ac in this condition otherwise you will chock and destroy whole system.
If you visit Rawalpindi, You can visit Eastern Car ac in Saddar, Rawalpindi having good reputation in twin cities. They are expensive but best in their work. I recommend you if you visit Rawalpindi.
You can also go to 3s dealership for checking whole system. They are also good.