No, it's not done, and there is hope of restoring it. It'll just need some work on your end of things. Shut down your MacBook, and restart, holding down the command/Apple+R keys together. This should get you into the Recovery partition, which will allow you to re-install the OS, check the hard drive (or SSD, as is the case) and reset the login name and password, if need be. If that does not work, try plugging in an Ethernet cable to your MacBook, and reboot, holding down Command/Apple, Option and R together. This is Internet Recovery, and will show a spinning globe on the screen. It'll try to get you the most compatible OS for your MacBook that it can. I'm sure there are others who will reply here and help you out.
john b