They face deeper isolation and tougher restrictions
Unpaid carers say they are worried about how they will cope this winter as coronavirus restrictions tighten.
Almost 6,000 unpaid carers completed a Carers UK online questionnaire with eight in 10 saying they had been doing more, with fewer breaks, since the pandemic began.
Around three-quarters said they were exhausted.
Some 58% of carers said they had seen their physical health affected by caring through the pandemic, while 64% said their mental health had worsened.
People also said day centres and reductions in other services meant the help they once got had reduced or disappeared, leaving many feeling worn out and isolated.
Helen Walker, chief executive of Carers UK, said: "The majority of carers have only known worry and exhaustion throughout this pandemic.
"They continue to provide extraordinary hours of care, without the usual help from family and friends, and with limited or no support from local services.
"It's no surprise that carers' physical and mental health is suffering, badly.
"I am deeply concerned that so many carers are on the brink and desperately worried about how they will manage during the next wave of the pandemic."
Carers UK is also calling on the government to ensure that those receiving Carer's Allowance - the main benefit for people caring 35 hours or more every week - receive an equivalent payment increase to those receiving Universal Credit.
This would provide £20 a week extra to help cover the extra costs that caring will inevitably incur over the winter months.
One carer said: “It has been the hardest six months of my life and I am dreading another lockdown.”
Another told the charity: “I am a shadow of what I was before going into lockdown. I am lonely, fed up and depressed, yet I can’t show these traits and must carry on my caring duties, no matter what.
“It worries me that carers who are in the same position as myself will be feeling the same and may do drastic things to escape.”
Caroline Abrahams, Age UK charity director, said: “It’s essential that the government works with local government and the voluntary sector to try to ensure that every carer is offered some kind of break.
“Age UK also warmly supports the idea of a new deal for carers: it’s shocking that carers have not been given the same temporary uplift in money that has gone to recipients of Universal Credit and that’s an area which the government should immediately address.”