something is making knocking noises

Look closely at the A/C Compresser pulley I would bet it broke apart. Some shops have the equipment to replace just the pulley/clutch assy without replacing the entire compresser. I hope this helps you

You are hearing the temperature blend door knocking/tapping in the dash. The temp actuator is worn out/attempting to reach the far left or right position but since it can't it just keeps trying. Temperature Blend Door Actuator. Some are easy to change under the dash, some are not so easy ri access.

Actuators usually make a clicking sound

Can I drive like that?

Not if it's the A/C clutch, it will eventually lock yhe pulley up and burn the belt off. That will stop the water pump, power steering pump and alternator.