I too used to be like yourself; looking up perceived symptoms online, convincing myself I had cancer, was going blind, had the first stages of heart failure etc. Interestingly this started at about 15 years old also.
Like others have said: stop looking up your 'symptoms' online. I know it's easier said than done but you must. When you're doing your 'death research' (as I liked to call it at the time) online you are actively participating in confirmation bias - you are filtering the medical information you are reading making the worst-case-scenario fit into your self-diagnosis, ignoring the other information telling you that you're fine.
But consider that hypochondria is a result of anxiety - an anxiety probably completely unrelated to your health. If you can find a way to remain less anxious throughout your day-to-day life you may very well find that your hypochondria becomes suppressed as a result.
Sorry I cannot give you any direct step-by-step advice.
Last edited by Benjamin01; 06-02-2010 at 09:47 AM.
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