I've had a piece of jewelry since I was eight, and have recently lost it. How do I not flip my sh*t?

It had a lovely golden (or rather, previously golden; it had become mostly silver over the (almost) decade I'd had and constantly worn it) chain and a custom made line of colored glass arranged to look like a rainbow for its dangly bit. It was a cheap thing, only something like twenty dollars; I still loved it more than any single piece of "fancy", "real" jewelry my grandmother had ever (and has ever) shown me.

I wore it all the time, and took it off to cosplay with a friend for a few hours. Like an idiot, I stuffed it in my back pocket. I've since checked everywhere, and am ninety-nine point nine percent positive it's not going to be found. It's too small of a thing to put lost posters up for, and even if I did the odds that someone would have picked it up are slim to none (we weren't exactly in the "best" of areas).

I'm well aware of the fact that the necklace isn't something "important", like money or an irreplaceable photo of a loved one or a credit card, but damn if it wasn't important to me. I've had it for so many years, and have worn it almost constantly since I started highschool. And I do mean almost constantly. I wore it under the costumes of plays, and in my suit during swimming competition.s For gods sake, I showered in the thing. I even DREW myself in it when I made comics to spoof the random things my friends and I did or wrote them notes.

The point here being, the necklace was (as corny and as melodramatic as it sounds) a part of my identity. It was the only piece of jewelry that I wore, and the only item of clothing that I gave half a care about (I'm not "huge" on fashion).

My question, in gist, is: how do I get over this spectacularly insignificant item of dress, regardless of how close I may have held it to myself?