You're just not used to seeing yourself in flats yet. It always takes some time for our eyes to adjust to new styles. You just need to learn to embrace your petiteness instead of fighting it!
Also let me say this: When else everyone is in flats and sneakers, it's the person in stilettos that looks "ridiculous." I can't tell you how many times I walk through the train station or on campus and see women teetering around on 4" stilettos, and think to myself how silly they look because their footwear is just totally inappropriate. Urban college students don't need to be running around in heels, just like a mom at a baseball game doesn't. There's something to be said for dressing the part. Lately I've been seeing a lot more women wearing flats for the commute and keeping heels in a separate bag to change into at work, which is a great example of practicality and style going hand in hand. Heel dependence is not a good thing and your feet will pay for it. Give them a rest! Once you get used to the look you'll wonder how you went all that time without it.