1999 Chevrolet S-10 X model engine

My air conditioner was working fine until the other day when it started doing something weird. All of a sudden the compressor would turn off and on fairly quickly. Then all of a sudden it stayed on for a very long period of time( in which it cooled perfectly ) then it went off for a long period of time.
The engine is doing what it is suppose to do at the right time, in other words the idle picks up when the air is supposed to kick in but the air doesn't come on everytime.
Can you help?