I have just put my six-week-old baby's car seat in the cart at Babies "R" Us. I think we will be able to make it without incident — Pampers and out. This is my first baby and our first shopping trip solo. We have no choice. There are no Pampers left. And there is poop.

I fantasize that someone will peer into the cart and say, "Oh what a beautiful baby! So quiet! So content!" And that person will think, What a good mom that woman must be!

But as soon as the automatic doors close behind us, Blair starts to scream. The cries should sound familiar to me since, over the past six weeks, I've listened to them, constantly, for 10 or 11 hours a day. But they don't, because the cries are now ricocheting off the three-story-high ceilings, echoing down the aisles, filling up Babies "R" Us like a sonic boom. People start turning around.

These people don't care that I've slept a total of ten hours in the past month, that I haven't showered in three days, that I'm still — still — wearing maternity pants. They don't care that I can't figure out what I'm doing wrong breast-feeding that's keeping Blair from gaining weight, or what I'm doing wrong generally that's making her cry so much. They don't care that I call my husband at work hourly, sobbing so hard that I can't speak, can't ask him the question that's been clogged in the back of my throat for the past six weeks, Have we made a terrible, horrible mistake?

I bounce the cart up and down while inching toward the Pampers because we need the Pampers and I just can't leave, because this is my life now. As we pass the stroller department, I hear the voice of an older woman say, "Why doesn't she just give that child a binkie?" I begin to jog. I remember the mass of maxi pad that's taped between my legs to catch the blood and yuck that's still leaking from my body. I feel it shift. I feel it poke out of the right-leg hole of the enormous mesh underwear the maternity ward nurse sent home with me, threatening to break free, to slide down the leg of my black XL sweatpants and land in a clump of gross on the floor. I do not care.

I grab six packs of the Pampers, which is way more than I need but I don't care about that either, because hell knows we aren't going to be trying this shopping thing again anytime soon. "Hang in there, kiddo," I say to Blair, as we cut a path to the front of the store. "We can do this."

Except, when we get to the register, I realize I don't want to do this. I want to walk out of Babies "R" Us and leave Blair there, wailing, the V-shaped blue vein popping out of her forehead. Nice people work at Babies "R" Us. Surely someone will take her home and care for her and buy her pretty things. I look at the door and picture myself walking through it, into the parking lot, into the minivan, into my life as it was before, where I was a confident, able, reliable person. Where I laughed at myself. Where I never, ever felt the urge to run away from anything because it was hard. I feel my hands letting go of the bar on the cart, my body turning away, my right foot lifting …

"Is your baby okay?" asks the woman working the register.

"Yeah, she's just colicky," I say. But I'm not okay, I want to tell her. Something is wrong with me. I was so confused when, last week, my OB-GYN said I didn't have postpartum depression. I wanted PPD. I needed a diagnosis, a word, some official terminology to explain to my husband, and my mother-in-law, and this check-out lady at Babies "R" Us why I'm totally sucking at this mommy thing. Why I'm the only woman on the planet who doesn't have a maternal gene. Moms are supposed to instinctively know what to do, right? Every mom around me seems like she knows what to do. I don't know what to do.

Well, guess what? None of us know what to do. Not knowing what to do is normal. Freaking out? Normal. Not all over-the-moon about the baby? Normal. Wanting to kill your husband? Normal. (And, FYI, it doesn't end. Because we are always new moms … always facing something for the first time … always praying to God that we're making the right choices and cooking the right dinners and buying the right toys.) Of course, when my first was born, it took me nine months to figure this out, to get a grip, to realize that everyone — everyone — struggles with becoming a mom in one way or another. It took me nine months to discover I wasn't alone.

So I'm telling you now. You are not alone.

Vicki Glembocki is author of "The Second Nine Months: One Woman Tells the Real Truth About Becoming a Mom … Finally" and also a featured blogger on Oprah.com with her blog Blunt Force Mama.