West Ham face Accrington in the EFL Cup on Wednesday night struggling from back-to-back 4-2 defeats to Watford and West Brom in the Premier League.
"Very soon it is that time in the league when you can get in trouble," admitted boss Bilic.
"We have to act, and very soon you can get out of trouble but it isn't going to happen by default.
"We have to do it. Starting from tomorrow we have three mega games, three cup finals before the next international break.
"This game is a good opportunity for us, it's an interesting competition for us. It's good to have a game tomorrow night."