"We have a big job to do over the next couple of weeks," he said.
"January can't come quick enough. But I think that, with what we have got in the club, and the two or three I will bring in we have enough to get out of this situation.
- Chesterfield 2 Mansfield Town 0 - Report and photos
"The lads know they are responsible for what is going on and the buck stops with me.
"We have got to stay together and try like hell to get a result against Peterborough.
Dearden watched his struggling side lose 2-0 in the big local derby at Chesterfield and said: "Obviously we are all very disappointed, particularly for all those fans who stood behind the goal in the rain and we gave them nothing to cheer when we attacked that end in the second half.
"There is nothing worse than losing a derby match. But we have to put this disappointment behind us quickly.
"After the first 15 minutes of the first half I thought we had a good spell of 20-25 minutes when we might have got a goal.
"But I was disappointed with our second half performance.
"For their first goal Mickey (Boulding) was taking on one of their lads and the ball just caught a heel and they knocked it long and we were not concentrating.
"Jack Lester put it away like he can do and you can see they have missed him while he has been injured.
"We probably should have handled him better but he was the difference today as was Jamie Ward who caused us a lot of problems with his pace."
Former Stags Kevin Gray was red-carded for a lunging tackle on Simon Brown near the end and Dearden added: "After the red card we didn't use the ball as well as I expected us to.
"I am not sure if Kevin should have been sent off. It was probably one of his rash moments and some refs would have sent him off and others wouldn't. But knowing the lad I don't think it would have been anything intentional."
Midfielder Stephen Dawson will need a fitness test on a badly bruised ankle before the visit of Peterborough.
And he is already out of next Saturday's home clash with Accrington as he will serve a one-game ban for picking up his fifth yellow card of the season.
Dan Martin also faces a fitness test to see if he can rejoin the squad after shaking off a hamstring injury.
And big striker John McAliskey is available again for the Peterborough visit. He missed the game at Chesterfield due to a family bereavement and was attending the funeral in Scotland.
