I have been using V for about two years now and for the most part it has worked like a charm. Recently, however, I have had some episodes where I could tell it wasn't really effctive. I was still able to perform, but it was not consistent and could tell the effectiveness was not the same. I have read that your body can start growing a tolerance for it and it could lose effectiveness that way. I don't want that to happen. Do you think its worth just taking a break from using it (a few weeks or so) could help?