How do I calm myself down when something bad has happened? I've tried prayer, meditation & exercise.

When something bad happens we can struggle with understanding why it happened to us, how someone could do something like that to us, and then with how to move forward.  In order to move forward from a situation we have to process it.  To process it we have to identify our feelings and thoughts related to what happened, feel those feelings, understand those thoughts, identify whether or not those thoughts are rational or irrational, and then challenge any thoughts that may not be rational so we can correct them and change them. 

So some thoughts could be - "this shouldn't have happened to me", "I didn't deserve this", "why would this person do this to me", "what did I do to deserve this", while some feelings may be, "I'm angry", "I'm frustrated", "I'm confused", "I'm hurt". 

Now that you know those are the thoughts: are those thoughts valid, was this personal, do you know the person's intent, does the person's intent matter? The reason those questions are asked is because sometimes people's actions say more about them than you, and are personal to them - not you, they could be jealous and frustrated with their own situation. Either way, when people antagonize people they don't know, it is typically because of something that is going on with them and tends to have nothing to do with the person they antagonize.  

Then when you examine your feelings, you look at the validity of those feelings. Are you angry that this happened to you or angry that someone questioned your personal integrity and antagonized your character? Are you hurt because this person didn't know you or hurt because this person criticized your image and made others question who you were as a professional? What is the actual feeling you are feeling and why?

Once you identify those thoughts and feelings then you can begin to look at how do you move forward. And moving forward requires identifying statements that remind you of the facts but allow you to move past the situation. For example, "I didn't know this person and they didn't know me and I know that I am a professional and the situation was resolved so neither them nor the situation require anymore of my attention". In order to move forward, you have to process what happened.