First thing to check is the air valve on the sink....make sure it's not blocked. It's that thing sticking up on the back side of the sink that seems to not have any purpose. If you look under the sink, you will see it tee's into the drain hose for the washer.
Next....if your seeing food in there as well, I'm going to say that your chopper is bad. Connected to the pump is a disk that turns with the pump....all the water is pulled through this disk that basically looks like a disk with holes in it....it's purpose is to chop up the food so that it will go down the drain without damageing the pump.
It's not unusual for the chopper to get a bone or something hard in it and the shaft breaks.
If you pull off the kick plate, you should find the schematic on the back side. And the internet has a ton of info on how to pull the machine apart.
When I replaced mine, I think the part was like $26.