Not having a good day

Today was not a good day.

A situation arose at work that left me really cross and frustrated and no amount of trying to focus on other stuff made me feel any better. I struggle with how to handle these sort of situations because, as a Christian I feel guilty about being cross with someone else and I often end up keeping my anger (even justifiable anger) inside. I also know that there is a spiritual (and psychological) cost in keeping a lid on things but I worry that I'll seem unprofessional, or stroppy, if I let negative feelings out.

How do other people deal with feelings that feel overwhelming, or get in the way? And is 'niceness' a face we hide behind that stops us changing the world into the place God longs for it to be?

I'm probably just making a fuss.... - is it a Christian thing, or a gender thing... or maybe it's just me????

What do you think (and no I'm not telling what happened because that really would be unprofessional!!)