Hi dandylin, sounds like she didn't give you a choice other than to document things and report to your boss. You clearly tried to help her but you can't make someone accept help, so maybe this just isn't the job for her for one reason or another??
But really well done on having the strength to stop trying to "carry" her!!! It couldn't have been easy for you
Hopefully she'll either improve if HR addresses it with her or, if she's fired, she'll be able to eventually move onto a job which she can enjoy doing. It just couldn't carry on the way it was, right??!!
And got to say........real credit for you having hung on in there despite what's been going on and still managing to like the work itself!!! Keep it up!!! And hey, don't forget to reach out for support when you need it too, we're here for you

Alison