The Chihuahua theory of recovery.

Let's say your issue is you once got bit by a German Shepard.  You were left so scared of dogs that even hearing a dog bark gave you a panic attack.  A dog food commercial on TV leaves you diving for the remote to change the channel.
So how do you recover?
First thing is to get the idea that yes, some dogs are dangerous, dog bites happen, once in a while someone dies from it.  Life has risks, people also get trampled to death by cows once in a while.  Study dogs in books, articles.  Talk to dog owners and breeders when there are no dogs around to confirm that only some dogs are dangerous, not all.
Then, start once in a while looking at pictures of dogs in magazines.  Pictures aren't dangerous, you might get a LITTLE panicky at first but that will pass as you get more used to them.
Then watch a movie like LASSIE, BENJIE or AIR BUD.  Notice that like you read and heard, most dogs aren't dangerous.  You might get a little panicky, but that passes as you get used to the idea that yes SOME dogs bite, but not ALL DOGS.  Remind yourself that technically, more people die from slipping in the shower than animal attacks, yet most of us manage to bathe.
 
Then go somewhere people walk their dogs and watch from a distance.  You might feel a bit nervous, but that passes as you get used to it. 
 
Big step.  Find someone with a tiny Chihuahua, ask if it's friendly, and give it a dog treat.  It weighs 4 pounds, not at all dangerous.  You'll be nervous, and MAYBE it will bark.  But even IF it bit, it weighs 4 pounds.  Paper cuts hurt worse, right?
Getting the idea?  Take whatever scares you, and find ways to make it less scary by getting used to it, bit by bit.  See that the dangers are exaggerated by whatever scared you of it in the first place.
The world IS dangerous sometimes.  This isn't a Disney movie.  But it isn't a horror movie either.  And sooner or later we die and sometimes we get hurt.  But it isn't often, and it doesn't last as long as we worry it might.  And in the end even if you die from a sharknado, hey, that's life.