The Baggies' 2-0 home defeat to Norwich was their third in succession after previous losses to Newcastle and Manchester City, although Albion had more than enough chances to take at least a point against the Canaries.
It also extended a longer sequence of just one win from their last nine Premier League games and leaves them just two points above the relegation zone.
West Brom's next two matches are against Cardiff and at home to Hull and Clarke has told his players they need to roll up their sleeves in order to get their season back on track.
"There is no other way," he said.
"It's been a difficult week for us. Three defeats in a week is sore, it's painful, it's hard to take but next week we have to go to Cardiff, we have to be resilient and we have to start getting points on the board.
"There is no easy solution.
"This was two teams who had not been getting the best results recently, feeling each other out. From nowhere they got that first goal, it gave them something to hang on to and set us back a bit."