An exorcism is only for those who are truly possessed. Even those who have been in the occult. Listen when someone is possessed it's pretty obvious. And very rare.
Garrigou Lagrange in his three ages of the interior life talks about the difference between obsession (much more common) and possession.
I would recommend getting holy water from a resistance priest (ask him to mail you some.)Pretty sure you are allowed to dilute it down somewhat, but talk to a priest about that cos I'm not sure how that works.
And sprinkling daily, if not twice daily
Then everyday say the August Queen of Heavens prayer, which are Lady promised expels demons.
The Holy Face chaplet as often as you can also. Each one of those "Arise O Lord.." expels demons on the spot.
And most of all pesevere in prayer, even if you find yourself losing concentration.