Is there a term to describe someone who becomes very worried after reading health information online? They think they have developed those health problems and are always on edge.
It's called cyberchondriasis - combination of cyber and hypochondriasis.
A type of hypochondriasis that develops in a person who, while on the Internet, identifies one or more personal symptoms—e.g., tachycardia, dyspnea—and ties that to one or more conditions; the individual then convinces himself/herself that he/she is suffering from these conditions (freedictionary).
That person would be a hypochondriac.
The persistent conviction that one is or is likely to become ill, often involving symptoms when illness is neither present nor likely, and persisting despite reassurance and medical evidence to the contrary. Also called hypochondriasis. 2. Plural of hypochondrium.
If you fear that you might be a hypochondriac then click here.
This sounds very much like a variant of the condition known as medical student's syndrome or medical student's disease
Medical students' disease, also known as hypochondriasis of medical students, medical student syndrome, medical student disorder, medical school syndrome, third year syndrome, second year syndrome, or intern's syndrome, is a condition frequently reported in medical students, who perceive themselves or others to be experiencing the symptoms of the disease(s) they are studying.