If you are ill but it is not an emergency, you can phone 111 for expert medical advice.
If you are worried about your health, you can ask your local pharmacist or visit NHS Choices to explore your symptoms and find out what to do about them.
Once you have been diagnosed (by a doctor) with a long term condition, there are many ways to 'self-manage' - look after yourself so that you can carry on with your life. You might need to make some changes but it often doesn't need to rule your life.
There are also lots of ways to stay healthy - and lots of services and support to help you with this.
These pages list NHS services, support services for long conditions and services to help you stay healthy.