Johnson told BBC Radio Cambridgeshire: "It's a difficult time because nobody likes losing football matches.
"However it's a situation I've been in before and I've come out the other end and finished in the promotion places."
Johnson only arrived at London Road in April and has been working to rebuild the Posh squad in the wake of relegation from the Championship.
They started the season strongly, but have been heavily beaten by Brighton, Charlton and Southampton in recent weeks.
Jim Gannon got performances out of limited players like Geohaghon and Green, Johnson can't get performances out of players like Boyd and McCann.
Ofori-Twumasi
"People are disappointed but it sounds a lot worse than it actually is and we have to remember we're just 17 games into a 46-game season," he said.
"There's a heck of a lot of the season to go and we have to stay very focused and keep believing."
Posh owner Darragh MacAnthony is backing Johnson to succeed, but has warned that he expects to see an improvement over the next month.
The former Bristol City boss has said he remains confident his men will be competing for promotion come the end of the season.
"At the beginning of the season Southampton and Charlton were having the crisis meetings and everyone will have good spells and bad spells," he said.
"There will be ups and downs and you just have to get it right when the 46th game comes around."
Source: BBC Sport
Source: BBC Sport