Well, for sure, you have a small leak!

Small leaks are very hard to find.. techniciasns should use a "freon dectector" I call it a "sniffer".

Its a device that senses the freon.... I makes a beeping (beep, beep, beep) noise and when it senses the freon, it makes a straight beep noise (beeeeeeeeep)!

That device is only for R-134a type of coolant though!

They can also use a dye...If you have a leak, it should be visible with a black light! You put it in the AC system and and let the AC run for a few minutes. ..then you turn off the light and look for the leak with a black light!

Check your compressor to see if the clutch kicks in...