If you have the energy, you should please try going out at night. I started at 3am then came home, then went back out at 5.30am and was convinced I heard my girl. I kept looking for another two hours and she was there. As it was so quiet, it was very easy to hear her. I too thought the worst, but I found this motivated me to search even harder for Izzy. She's now lying next to me in bed; she's grounded, but as selfish as it is, I'm delighted to have her home.