Ok lets tackle a few things first. First and foremost, you're not going to hurt anyone. There are two lines of thinking that people have on this board pertaining to having "intrusive thoughts." First of which is that these thoughts mean nothing and everyone has them, and the best thing to do is just not pay attention to them.
The second line of thinking, and what I personally believe, is that these thoughts are conjured up by your sub-conscious to get you to pay attention to something that is happening in your life that is really bothering you. Having "intrusive thoughts" is part of being OCD, and these thoughts are symbolic and not literal. People don't like change, anxiety, anger, stress, and we have different reactions to these things and our sub-conscious knows this, so since we might not willingly acknowledge them consciously, our sub-conscious still thinks about them.
You said after dealing with these thoughts for an extended period of time you go into a "dream world" or you feel depersonalized. Well that's because your brain can no longer put up with thinking about all these things, and basically your brain just says, "I'm tired of putting up with this," and shuts off. This is called a disassociative phase, and it's a good thing becuase it shows that your brain is being deffensive and reacting to these irrational thoughts. One thing you have to remember is that you don't want to have these thoughts and they BOTHER you. These thoughts would not bother someone who is not of sound mind or has some other serious psychological disorder. We sometimes have these thoughts because, as strange as it may sound, were trying to protect ourselves. Example? If I'm in the hospital, I'm away from things that cause me anxiety. If I think this way I'll scare myself so much that I'll avoid the situation. We AVOID conflict, we AVOID stress, we AVOID change because it makes us uncomfortable. OCD is just another way that our brain gets us to avoid things that make us uncomfortable. If we have these intrusive thoughts, we don't have to think about what's really bothering us because were so distracted thinking were crazy or nuts. It's the ol' "bait and switch."
My advice is to get into see a good cogntive behavioral therapist that specializes in anxiety disorders and OCD becuase they have the most experience dealing with OCD. Also medication is fine, but should always be used in conjunction with good therapy.
Hope this helps!