Can I vent here?

Jill
I must preface with this: I do have one child and I am so thankful. I know there are others out there with no children who desire more.
Last night I took daughter to Chik-Fil-A for a play date. Across the room was a little family. All beautiful, what looked like an entire litter of children. And my thought was wow, such cute kids. They are blessed. Then the mom turned around and she's very noticeably pregnant. Suddenly, I'm just angry. Why is it so easy for some and so difficult for others?? And, lately, on the news there's these stories of people harming or killing kids. 
I'm currently at the OBGYN office for an ultrasound mid cycle to check out my eggs. I'm sure there's a more scientific name for whatever. I didn't really listen. 
Discouraged...