I have been on Zoloft (sertraline) 12.5mg for 3 weeks with the most horrible side effects. I no longer want to take this medicine. How do I get off of it?

Talk w/doctor. First, i suggest talking with your doctor about your decision. The zoloft (sertraline) must have been prescribed because of some symptoms you were having, and these may still need treatment even if zoloft (sertraline) is not the best option for you. You also haven't mentioned what "horrible side effects" you're experiencing -- but i'm sure your doctor would want to know so that something more helpful can be given.