[pogodzib]

I'd clean the pump and air line and see if that helps. If not, something may have gotten into the water that is preventing the skimmer from functioning correctly. The one thing that you don't want to do prior to taking off is clean the skimmer or make it function differently and then have it go nuts and overflow when your gone for a few days and come home to a mess on the floor. Your tank will survive for a few days or more without a skimmer without showing any (or at least minimal) negative signs.