You probably have a refrigerant leak. You can keep refilling it yourself every once in awhile or have it fixed at a shop which is far more expensive. If it's a small leak it could last a couple months before needing to be refilled again

Call an mechanic...check it first otherwise you may have to replace it...I think refrigerant problem...

See a mechanic that specializes in auto A/C work and ask a lot of questions before reaching for your wallet

have it checked