It may not be a magical chant of itself, but the litany against fear of the Bene Gesserit from the novel, "Dune" could be useful to you. It goes thusly:
" I must not fear.
Fear is the mind-killer.
Fear is the little-death that brings total obliteration.
I will face my fear.
I will permit it to pass over me and through me.
And when it has gone past I will turn the inner eye to see its path.
Where the fear has gone there will be nothing.
Only I will remain ."
You might also consider doing personal shields for yourself to keep negativity away from you so that you aren't feeling so scared.
But if you find that your fears are controlling your life so much that you aren't able to enjoy yourself or do the things that you want to do you might also want to be evaluated by a medical professional to see if they can help you get at the root of your anxiety and help you deal with it.