I've been dealing with anxiety for years now. I suspect I have generalized anxiety along with social anxiety, but I've only been formally diagnosed with S.A. so I'll speak on that.

Basically, by changing my thought patterns, I can reduce my anxiety. 

I get anxious all the time about people "staring" at me. Maybe I'm anxious about walking funny. Also I have constant problems with self-diagnosing terrible physical ailments like Cancer (hypocondria, i guess).

When I'm really anxious I'll force myself to try and realistically consider my situation and what the probability is that, actually, i do e.g. have cancer. Instead i think I might have a minor ailment, or nothing wrong at all and i'm feeling normal bodily sensations. 

tldr try and actively challenge your negative beliefs