I used to suffer from severe anxiety a few years back but I got over it with help from a few months of therapy and one year of medication (5mg buspirone hydrochloride one tab three times daily). Anxiety can come in a few forms and one of them are intrusive thoughts, thats the one I want to talk about right now. If anybody suffers from anxiety they could be experiencing these if so to read up on them is extremely beneficial because if you gain some understanding of a thought process you can get real clarity on the subject and it can even help you to overcome it, even if you are not experiencing intrusive thoughts it can still help in some way because you may gain more understanding of the nature of anxiety. This is a very useful article, you may not know what intrusive thoughts are, or you may be experienceing them but not know what they are called in order to do any research. I know it very well because it was part of my therapy and was explained to me in depth. If one suffers from intrusive thoughts they are not insane at all, it is only linked to anxiety and a few other mental health problems but not actual insanity.
So if you have come across this thread whatever ailment you have then please read this http://en.wikipedia.org/wiki/Intrusive_thoughts it could help a lot and even if it doesn't it really wont do any harm to take the time to read it.