Sweetie - don't worry about "wasting every body's time" - Seriously - YOU are the bride! It is the ONE day you get to be the center of attention! And you should, and you DESERVE to look beautiful! This is all coming from me, a 3 dress bride LOL! You look beautiful in that dress you picked out, but if it doesn't feel like *the one* I certainly think you should go try. My 3rd dress, that happened to be the one, I bought from DB rigt off the rack. It was brand new, luckily, and it fit me like a glove. I loved it. And I'm so glad I bought it! So the point is, take the dress with you, try it on with a veil and shoes and jewelry and if you still don't love it keep trying on dresses. Make sure you bring a camera, and don't make any decisions that day.
Wait, go home, look at the pics, sleep on it, and the next day make your decision. Good Luck! I was SO in your shoes once, and I never regretted buying my dream dress.