That sort of stuff just happens sometimes in this hobby, and she may well die. Your situation almost certainly isn't your fault; it happens to everyone. Best case scenario, she burned through her fat stores, and you can replenish them by giving her a tiny bit of honey or a cricket leg to eat. The loss of her workers may also be the cause, so if you feel confident in your ability to locate an identical or closely related Formica colony, you could steal a few wild cocoons and give them to your queen. Sadly, she may have just experienced some inexplicable failure of the reproductive system. Good luck and I hope she pulls through!
Tetramorium immigrans, Pogonomyrmex occidentalis
Formica cf. pallidefulva