Possessed by demons, or the devil?

Now before you go ahead and label me crazy, I'll have you know that I have no mental problems or anything of that nature. I don't believe much in supernatural phenomena, or paranormal. I don't believe in a higher power like God, or even the devil. Its not that I'm ignorant, I just choose to believe in ones self. To me religion is a crutch for the weak of mind. But something rather odd has happened to my life over the past few years that I cannot explain.. I make wrong choices even though I know whats right & its like I can't help but to do these things. I sleep more frequently than most, & my dreams have gotten very vivid.. a lot of my dreams are nightmares witch are very morbid and I don't even know how my mind even creates such savage thoughts. But the worst of my issue happens when I'm either very tired, or drunk. I have been able to handle my alcohol just fine in the past, but just since the last 6 - 7 years its been different. I reach a certain plateau, and once I reach that I black out. During these black outs strange things have happened. I don't want to really go in depth with what happens during these black outs.. but its like something else takes over. No longer am I really me, I become something very wrong. Just wondering if anyone really believes in possession? and if so, how can you rid yourself of this? & No, its not like the movie excorsist or anything that extreme.. but its something. Anyone have anything to say about this?