Problem with my riding lawn mower?

I have a Yard Machine tractor mower, model number 13AN772G000. It cuts fine, and drives like it should, the problem is that I can't do both at the same time. If you're driving it and engage the cutting deck, it just stops. The engine continues to run, but yo get nothing. The last time I used it before it started doing this, I hit a reasonably sized stick. It banged around for a second and then it was fine, and continued to cut the rest of the yard. Does anyone have any idea what might cause this? I can't afford to take it to a shop or buy a new one, and my back can't afford to cut the entirety of the lawn with the push mower. Please help.