It can unfortunately do what you just said, that is time to switch I am sure. Personally, I wasn't on it too long and di not find it so great for my depression problem, I have had prozac, zoloft, wellbutrin, effexor, remeron, and celexa was the last antidepressant before my wonder drug, Lamictal (actually a med for epilepsy but helps bipolars).
Don't be afraid to ask the doc "so what do you think might be a good med to try?" Or "I heard about (drug name), do you think it can be of help to me?" Such questions can open up a line of communication between you and your doc.
Just my 2 cents
"darkeyes"