Hi Paukki.
From what you describe, it sounds like this may have originated from your smoking pot days.....Marajuana and drugs can leave you vulnerable to obsession and other nasties. Mediumship can also be very dangerous in regard to these issues....but you said you did not participate in that.
The only thing i can recommend at this point, other than a *true* prayer warrior (very rare these days), is the invisible helpers.
If anyone can help you, i believe they can.
Check it out:
http://www.rosicrucian.com/healing.htm