Yup, pretty common.
When this happened to me the advice was to just find an NOS surplus halfshaft, rather than mess with pulling the old one and dismantling it to put on a boot. It is MUUUUUUUUCH faster to replace the whole thing, and when I needed mine they could be had for a reasonable price (<$150).
I advise pulling and replacing the entire assembly. You can sell or store the removed one for other uses/spares. My two removed ones are helping keep part of my garage floor occupied, and doing a great job of it...
If you are patient, and clean it thoroughly, you may be able to tape your torn boot in place with wide electrical tape or another flexible tape. It isn't a great solution, but helps keep what remains of the grease inside where it is needed. It at least slows the leak. I wouldn't go off-roading like that, but you can drive around at least.
Bulldogger