Jonathan
If this is one of the "oiless" compressors, this is how they generally act when they die. They just start working less and less, to the point they can't even fill the tank anymore. I would check if it us under warranty, and see if there is anything you can do that route. If not, in my opinion I would suggest going to an oiled compressor which will last much longer. Use a quality compressor fluid in a good oiled compressor and it will last a lifetime.