Three in four small charity leaders say that worries over funding keep them up at night, according to a survey conducted for the Weston Charity Awards.
And one in three says that worrying about their own ability to do the job does likewise.
The online survey of 371 small charity leaders was conducted by Pilotlight, a charity which connects businesses with charities, and by funder the Garfield Weston Foundation, as part of its work on the Weston Charity Awards, which give core grants to small charities.
The survey mostly polled chief executives of charities under £500,000, and found that despite most of them being worried about their ability to continue delivering, optimism was on the rise.
Of those surveyed, 38 per cent expect to see an increase in funding, compared to only 16 per cent expecting to see a fall.
And 78 per cent said they expect to help more beneficiaries this year, compared to 58 per cent last year.
Small charities also expressed mixed feelings about the support they received. While 81 per cent said local people provided good or excellent support, 82 per cent said they did not get the support they needed from central government, and 45 per cent said they did not get it from local government.
Despite the difficulties, small charity leaders said they love their jobs, with 83 per cent saying they would recommend working for a small charity to a friend.