Hi, your history is suggestive of hypochondriasis. It is a psychiatric illness which takes lot of effort, time and consistancy with treatment. Instead of changing doctors, stick to one, go for regular followups, attend therapies. It is a slow process. Trust, patience and consistency is the key.
Next Steps
can consult for more clarification.
Health Tips
understand your underlying anxiety
practice relaxation techniques
do your research on illness anxiety disorder
select and stick on to one psychiatrist for good response.
wish you speedy recovery.