I assume you're from the US, because where I live (Italy) complaining about pregnancy, motherhood and one's family is pretty much a national sport. Sometimes it gets kinda graphic (I've been scared out of having kids forever by lenghty recountings of childbirth, detailed descriptions of projectile-vomiting babies, and nighmare-inducing tales of birthday parties and 5-hours-long parent-teacher conferences) but at least raising a family is not talked about as some magical, enlightening, 100% wholesome experience you should be thankful for and happy about every minute of your life.
I know tons of caring, dedicated mothers who still groan on a daily basis about how their kids are messy, troublesome brats who steal all of their free time, and how they should have stayed single and opened a bar on the beach instead - nobody bats an eye at them.
"Having kids sucks ass" is something I hear all the time, and more often than not I've heard it from really good mothers - so maybe grumbling about one's life keeps stress levels in check. Complaining doesn't make them bad parents - it makes them human.
So do like Italian mothers do: huff, puff and complain all you want!