2006 dodge Durango 5.7 hemi

When I put my truck in drive or reverse, step on the gas it won’t drive I can push the had all the way to the floor and it moves a short distance very slow, like it had no power. We changed the front brakes Friday, but it drove fine Saturday. Today we pulled the air conditioning fan out from the inside of the vehicle and put it back in, and now is doing this, we’ve never had a problem like this before