If you need to cry, cry!  Stuff what other people think.  Regardless of whether something has happened in work or in your personal life, your body will react and need to do what it needs to do.

Is is ok to insult people or belittle them at work?  harrass or bully them?  I think not, so cry if you want to!  

One year on after the sudden death of my father, I get very emotional, sometimes for no reason other than a thought will enter my head or someone will say something.  I have of course got up from my desk and taken a few moments to compose myself or had a chat with a colleague, but no one has any right to question how you feel and certainly not your reactions.  

(Sorry if that sounds harsh, but it's reality).