It is usually very painful when you are betrayed by a trusted friend especially one you repose so much confidence in. betrayal by a friend is worse than the venom of a serpent and this kind of shock if not well managed can have very indelible mark and psychological effect on the recipient of this betrayal.

In order to overcome the shock that arises from the betrayal of a friend, it is always advisable to keep the mind open to anything because we live in a world where trust is a foregone conclusion and can only be gotten on a chance basis.
Instead of brooding over this sort of betrayal, it is best if you allow events pass by and move on, forgiving the offending party and continually keeping your mind open to even ore betrayals so that when they eventually come, there would be no shock or trauma for you to manage.