Welcome to the beyondblue forum. It is great that you are reaching out here to gain some further information about your health anxiety. I have responded to several posts of this nature and encourage you to use the search feature above and type in 'health anxiety' to review others experiences.
Firstly, I want to assure you that having anxiety about health is very common. In the age of 'information overload' and 'Dr Google', people are more readily identifying with symptoms of many illnesses because this information is easy to access. The mind is very powerful place and the more you think about a symptom, the more alive it becomes whether it is truly there or not. I always recommend getting any symptoms checked by a GP. It is important to make sure that you a physically healthy and get an thourogh assessment.
In your post, it does sound as though your anxiety around having an illness is distressing you. I wonder if in any of your appointments with your GP you have mentioned your stress and recurrent worry? If you have not, it might be a good place to start.
Most people have some degree of worry which is normal. But when it starts interfering with things like eating, sleeping and being able to concentrate, then you might find getting some support to work through your worry helpful. The best place to start would be with your GP and possibly getting a mental health care plan so you can access a psychologist.
There are some online programs as well including one called Mindspot www.mindspot.org.au If offers online counselling specifically related to low mood and worry. This might be right for you if you are not comfortable talking with someone in person.
Another outlet is calling the beyondblue support line on 1300 22 4636 where the operators will talk with you about your concerns and you can gain some immediate support and recommendations.
Having worries about your health is common but when anxiety gets so bad that it starts to interfere with how you live your life, it is time to get some support. You have already started this journey by posting on the forum and now I encourage you to take this a step further by talking with your GP or someone you trust and getting some additional help so you can stop the worry sooner than later, before it gets out of hand.
Wishing you the best possible outcome,