this parent stuff

Oh man.
I'm reading the Harry Potter series again (actually, I'm listening to them - what a magnificent narrator, and I LOVE being read to), and it appears that I've become a COMPLETE SAP since becoming a mom.
I was SO looking forward to starting listening to these books again - it's been years and years since I read the Sorcerer's Stone, and there are some I only read once. So this morning, I settled in and queued up Chapter 1. All of a sudden, as the story started unfolding, and I was listening to a story about a baby who was Finn's age losing both of his parents and growing up for ten years without anyone who cares about him.
And then I burst into tears.
Not just once, but several times throughout the course of the first four chapters.

I've noticed that there are some things that affect me in different ways now that I'm a mom, particularly when it comes to kiddos and I've realized that I've become almost fierce in my feeling toward my son, like some sort of animal protecting its young. I've also come to realize that I have this welling up inside me anytime I see or hear about a child being abused in any way.

My question: How the HECK am I supposed to function when my emotions are so volatile? How the heck am I supposed to keep my head and "keep calm and carry on"if Finn is being bullied at school? And most importantly, how am I supposed to read Harry Potter to my kids if I'm bursting into tears all the time?
Sheesh. This parent stuff.