I've lost everything and I don't know how to get it back. How can I repair my system all I have is a usb with slax linux. I am freaking out because I had a lot of projects on their that I hadn't pushed to github as well as my configs and rice. Is there any way to repair my system? Can I get a shell from systemd?
Boot a live Linux, chroot into your system, run pacman again and fix your systemd boot to include a fallback option for the next time this happens.