crying again

Why do stupid things make me cry? Anytime something doesn't go my way I seem to just start bawling. I've never been like this before. I don't know how to make it stop. I was trying to get into a new Endocrinologist and the doctor isn't taking new patients (of course) and I can't stop crying! I just barely made it off the phone before I burst into tears!!!!
I AM SO FRUSTRATED!!!! Why is this making me cry? There are how many endo's in the world, and not getting into one makes me cry???? This is not me! I am usually a positive and optimistic person! I don't cry over lame crap like this!!!! WHO AM I?