Someone stole my cat and I can't stop crying?

I'm 13 and she is(was) so close to me and I love her dearly.. We found her as a stray 1 year ago (actually she found us- she came up to our doorstep starved and cold) and we took her in.. she's an indoor-outdoor cat and regularly went outside daily (I live in an apartment on the second story) and she always came back and was allowed to go back down again. We also checked on her every 10 minutes...and she came whenever we called her name. Today, though, there was no response from her after 30 minutes of frantically searching(NEVER happened before). I'm sure that someone stole her because she never does this and it has not happened before.. and because I've seen random strangers approach her suspiciously (which I would normally have supervised, because I'm down there more than half the time and constantly checked on her)