It sounds like your subconscious thinking through the feelings and idea of being sick. It’s a thin that thinks very symbolically, and it’s unlikely thee figure were beings, and more likely that they are representations of things in your environment.
Like, being poisoned representing that something external came into you that has make you feel bad, and “killed” you meaning you got a bit sick. It cold also be trying to warn you that someone did magick on you to make you sick… it hasn’t really worked but you can see the intent in the dream.
I would banish, cleanse and do a hex break as a matter of course. If you don’t have good wards around where you sleep and your living space or house, get that sorted out as soon as possible - things like this shouldn’t really be able to find you to cause you problems this casually, imo.
I assume you’ve seen the megathread with our protection tutorials but here it is again just in case, or use whatever works for you… doesn’t seem like the Mantras are kicking in yet, no reason to stop doing them but add something more immediate and aggressive that deals with issues after they started too.