I need motivation

DH's parents are coming over for the weekend tomorrow, the first time his mother has seen the apartment since we moved in (she has not been here since we've bought furniture and actually lived here). I, as usual, am responsible for cleaning the house and since his mother is very loud and judgmental and was a cleaning lady for a long time in her life... I am doing the very very best job I can do so that she'll have nothing but nice things to say to us... but I am tired and its fridayyy and DH and I just got into a fight on the phone and when he comes home I know its just going to escalate... and now i have no motivation to clean but the place is still half a mess. help!