I think that first of all you’ll have to provide more information on what you did before this started to happen and possibly some more details on what else the emergency mode “says”, so that someone can try to help.
As far as I can say, at a quick look into the forum, I see this could be related to grub problems or even EFI partition problems.
So, maybe you could try to start with this one:
At least check that your ESP partition is still there.
I think that also reinstalling the bootloader and updating the grub wouldn’t hurt anyway.