A doctor can't cure this one. A Case of the Mondays is an especially bad mood brought on by the onset of the workweek or the school week–which, for most of us, begins on Mondays.
Time to get the leash. The slang dog walk is "to overpower" or "outsmart" someone, as if in utter control of them, as when walking a dog. The slang verb own is a close synonym.