Can a demon do this?

Okay but you know, your case would be different. When you work with the demons the demons are nice to you but if the demons see that a person fears demons then the person gets indeed attacked by demons... But then again, demons are not always nice and demons are not always malicious either. So therefore, the belief of demons being malicious is never false. Even my friend who works with demons sometimes says that demons can be malicious. But I guess I should maybe ask a Christian priest to help me get rid of demons that bother or try to harm me... And I can say that the demon named Sitri tried to destroy my love feelings towards my crush once, because Sitri thought that it's bad to love a fictional character, andyes, my crush is a fictional character, but it is not forbidden or illegal to love a fictional character or to have a crush on a fictional character.

..........Go see your Priest, and then get yourself back to your doctor.

You have things going on that magic will not solve, and will probably only make worse.