I would think these are liver flukes, but if true, then I didn't know they can be vomitted. I hope you've put some of them aside in some suitable fluid to preserve them for anyone who's interested in finding out what it really is.
Sorry to read that you're still fighting these "demons", but I think it's a good thing that these buggers come out every which way; as inconvenient and bothersome as this must be to you.
Hopefully somebody is able to shed some light on the true nature of these expelled, unwanted freeloaders.