On my last vacation, I completely overstuffed my suitcase. When the blond clerk from our hotel on a Croatian island offered to carry my bag up to my room, I nodded yes at her nicely — after all, I could barely lift the hulking Samsonite. It was only after she turned around to leave the room that I realized, with horror, that she was pregnant.

This affront to all Eastern Europeans was just the latest in a series of lifelong mishaps stemming from my overpacking or packing poorly. Think my broken toe, crushed by my giant roll-on in San Francisco, or what I’ll call “Parisian What Not to Wear,” aka, the night I had to wear my husband’s kneesocks with dressy pants on a surprisingly chilly summer night in France.

Poor packing and excess baggage were literally starting to cramp my travel style — in addition to costing me checked-bag fees. (I hadn’t carried on a suitcase since Bill Clinton was president.) But how does a chick used to ferrying an extra 10 T-shirts to the beach or three pairs of boots on the Bolt bus to New York reform? And is traveling with too much stuff a sign of some deeper problem?

“I think people get anxious about having the right thing to wear when they arrive somewhere,” says Melissa Brown, owner of local personal-shopping service Lockstitch Style (Lockstitchstyle.com), who offered to help me pack — and rethink how I did it — for a six-day trip to California last month. “You want to wear staples, yet look good.”

For many travelers, suitcase psychosis is rooted in how they imagine themselves in a foreign environment — swanning around in high heels on the streets of Rome, lounging in a teeny bikini in Rehoboth. And, often, the reality — stiletto unfriendly cobblestones in Italy, no pool at your hotel — doesn’t match what they truly need to bring.

“I always think, ‘How do I want to feel while I’m away? What will make me happy in an environment I don’t know?’ ’’ says D.C.’s George Stone, a contributing editor at National Geographic Traveler magazine who admits to anguished, last-second suitcase stuffing. “I know how I feel today, but how will I feel tomorrow? Packing for a trip is really about navigating the future.”

For me, Brown suggested literally charting a course for what I’d be doing in Cali, then sketching out a six-day graph detailing outfits for every event (e.g., Wed.: Wine tasting: boyfriend jeans/black cami/sweater/flats; Thurs.: Dinner with hipster ex-roommate: striped maxi skirt, cardigan, black cami, chunky necklace).

“Write things down, and you’re less likely to double up,” she said. “Then, check the weather and take that into account, too.”

Brown and her assistant Benjamin Miller sniffed around my closet, choosing a few interchangeable pieces (see suitcase, at left). The resulting pile didn’t look like much, until Brown plugged it all into her graph. I had enough outfits for everything, with one extra top in case of Merlot-related mishaps.

Watching Brown and Miller neatly fold clothes and fit them into my bag, I realized I’d been packing like a middle-school girl out to impress the popular kids by wearing a different, cute outfit every day. But were the cheerleaders from seventh grade traveling with me? No. I’d be with pals who’d lend me a shirt or let me do a load of laundry.

Indeed, to avoid hiring Sherpas, anyone should be able to pack for a week in a carry-on. “Simple is better when traveling,” says Ada Polla, the D.C.-based CEO of Alchimie Forever (Alchimie-forever.com) and a frequent flier. “If you’re gone for five days and not re-wearing things, that’s ridiculous!”

Still, my inner clotheshorse bucked at not taking the vintage flapper tunic I’d just scored or an extra pair of yoga pants. “Are you going to a vinyasa retreat?” Brown asked. “And isn’t that tunic too thin for chilly San Francisco?”

If there’s a devil in overpacking hell, it’s most likely shoes. “People take too many, and shoes are heavy and use up a lot of room,” says Michelle Madhok, founder of the Shefinds.com shopping site and author of the upcoming, “Wear. This. Now” ($17, Harlequin). So, with Brown giving me a stern look, I narrowed my choices to comfy ballerinas, tennis shoes I’d wear on the plane and sandals for nights out.

When my 22-inch-high bag was packed and ready, the final amount of stuff was shockingly low. As I pulled the roll-on through the airport security line (skirting the queue to check a suitcase), I felt less travel stress than I had in years.

And in California, I sipped wine, hiked in the redwoods and went to a nice dinner or two, looking presentable-to-fashionable at every stop. And at the end of six days? I hadn’t even worn everything in my bag. Maybe next time, I’ll just bring a backpack.