Shalom, Rach.
Yeah, I don't believe in a pre-trib rapture anymore, either, but my father does, and as a minister and Sunday School teacher, he teaches that those who are left behind will be sent a strong delusion that they should believe a lie:
2 Thess 2:7-12
7 For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way.
8 And then shall that Wicked be revealed, whom the Lord shall consume with the spirit of his mouth, and shall destroy with the brightness of his coming:
9 Even him, whose coming is after the working of Satan with all power and signs and lying wonders,
10 And with all deceivableness of unrighteousness in them that perish; because they received not the love of the truth, that they might be saved.
11 And for this cause God shall send them strong delusion, that they should believe a lie:
12 That they all might be damned who believed not the truth, but had pleasure in unrighteousness.
KJV
So, even if they COULD be "saved," they WILL CHOOSE not to be.
(I used to have nightmares waking up and finding all the Christians gone, and I'd ask questions of myself like, "Am I sure I'm saved?" and "What if I'm not?!!" There was a point in my life when I was constantly going forward for the "assurance of my salvation." Scary! And, I'd scare myself on top of that when I'd come home from school and find no one home! ARGH! Sigh. So much time and energy wasted.)