1999 concord a/c problems

Ok, here is the deal, i was driving around town and the AC was working great then i stoped a a store for about 10 minutes then when i got back in my car the AC did not cool at all. none of the fuses are blone, the relays are all ok. i really just have no idea whats wrong... please help

You may need more R134A. Only guages will tell.

this has happened on my wife's twice now. The first time it was a bad radiator fan, the second time it was because the compressor failed.