I personally don't believe in "devils" in that way, or "spiritual attacks" -- I wonder if that gets me in deeper **** with the people here.
My reason for this belief is this: I feel that if we try to "externalize" evil or negative feelings too much (in the form of "devils", "demons", or "spiritual attacks"), then we reduce the responsibility of humanity for sin and for failings. I prefer to think of my sins and my weaknesses as being fully mine -- God does not have to protect me from supernatural beings, he has to protect me from myself. I am the sinner, and the devil did not make me do it.
For instance, in your post it almost sounds like you are saying that the weaknesses you felt were not really yours, but were being caused by some external force that you had no control over. I don't know if this is really what you meant, but that's sort of what it looked like to me.
(AFAIK the Catechism is silent on this issue, but I could very well be wrong -- I did a search for "demon" and "devil" and did not find anything directly relating to this.)
-Chris
