I have schizophrenia (schizoeffective actually) along with bipolar 1 disorder. I've had hallucinations, delusions, and psychotic episodes in my life and.. this doesn't sound like that to me. It is absolutely possible that your OCD is making you hear and think things that you normally wouldn't. Sometimes, we can be vulnerable to the feelings of others and this little girl was honest with you in that unlike most patients, she would never get to a 0 and maybe that made you uncomfortable because yours never went to 0 either. You fed on her anxiety while she fed on your calm. But, demons don't usually transfer targets like that. They're either attached to a place or a person, but not both. The only way that the demon could have transferred to you is if you had upset it during the session, but it would more than likely want to punish the host than you. So, I don't think that the demon attached itself to you either.

Logically, I'd say that if it would make you feel better, go to a local church of whatever persuasion you'd like and get some sort of blessing, sage your house, put up protection charms, create a salt barrier. Do any and all things to reassure yourself that even if nowhere else is entirely safe that at least your home is.

I would also say that it would be very rare for schizophrenia to manifest after early 20s and that even anxiety and depression can cause psychosis. But, this isn't psychosis, because you're still able to logic and coherently speak to yourself and others. You're still talking like you're within reality.

Maybe the stress and tiredness is causing auditory hallucinations. The less you sleep, the worse it'll get. So, try to sleep. You'll be okay. That's what I always tell myself. That it'll be okay tomorrow. Just get through tonight.