People say they are worrying more than they did five years ago, a survey has revealed.
Health tops people's list of concerns
Health, particularly heart disease and cancer, topped the list of concerns, with respondents concerned about themselves and their families.
But issues such as bird flu and terrorist caused less worry, the Bupa survey of 1,800 people found.
Doctors said experiencing some stress was normal, and that people in the UK were not 'unnecessary worriers'.
If the survey findings were extrapolated out to the whole UK population, it would mean 67% worried, and 21% of them were tempted to go to the doctor or get medication.
Bupa said stress-related medical problems are becoming increasingly common, with more and more people losing sleep because of anxiety.
More than a third of worriers surveyed are losing sleep, a quarter say they get annoyed, while 12% said they became withdrawn, and 11% shout.
Others turned to drink or comfort-eating to ease their stress.
A third of worriers say they tended not to do anything about their concerns.
And over half say they don't tackle their worries head-on because they hope they will go away or get better by themselves, while a third say it's because they are too anxious.
Two thirds of those questioned admitted worrying, with a fifth of these going to the doctor for treatment.
But many try to cope with their anxieties themselves, talking to friends and family, taking a walk, reading a book, or having a soak in the bath.
Dr Paula Franklin, Bupa Insurance's deputy medical director said: "This survey indicates that stress levels across the country are increasing.
"Almost everyone feels worried sometimes, but if you are experiencing frequent sleepless nights and anxiety, your worrying could be spiralling out of control."
People who were feeling stressed were encouraged to take regular exercise and eat healthy food.
Dr Franklin added: "There are lots of self-help techniques that can help you to reduce stress, and simple lifestyle changes such as ensuring you eat healthily and take regular exercise can also help."
Dr Mayur Lakhani, chairman of the Royal College of GPs, said: "Some stress is a normal part of everyday life.
"As a practising GP I do not think that the people of Britain are unnecessary worriers.
"Patients with prolonged or intense stress require skilled help and intervention especially if it leads to clinical depression and disabling anxiety.
"The important steps are self-awareness, prevention and seeking support often from friends and family."