hi hi hello!!!! um when this stuff happened to me I used to always think I was being attacked by demons, being haunted by ghosts, having ghost and demons trick me and follow me, but I discovered that the most likely origin of "demonic possession" is likely delusions and hallucinations from ancient cases of schizophrenia, schizoeffective, bipolar, and so on and so forth, because back in those days you could not treat those conditions so easily.
These days I have "considerations" of the possibility of my body being infested with demons (+more), but I try to only part-believe
If it makes you feel better, you can=
- pray to God
- cross yourself
- draw crosses
- imagine a holy light surrounding you
- sleep with the lights on
- read the bible
- listen to ancient church music (or modern church music if u want)
- read a children's book
- watch a children's movie
- if you have an animal, and you are feeling scared, look to your animal, and you will see that the animal may be calm, indicating that there is no ghosts or demon in ur house/room