I have been on Sertraline for almost 6 months and when I went to a follow up appointment I was concerned about weight gain and my doctor put me on Phentermine. I have been doing really good then all of a sudden I am getting the knots and burning feeling in my stomach Again. Feeling like I am going backwards. He suggested to only taking half of phentermine. I am feeling the anxiety coming back and now I am back to googling and tremors and panic attacks.