Hi, I'd like to help you with your question.
Fluoxetine, also known as Prozac, is taken to help depression and sometimes anxiety. It affects the serotonin in your brain, making more serotonin so you feel better. Fluoxetine is known to cause weight loss in the first six months. The weight loss then tapers off to be no different than a placebo. Some people have reported a weight gain, but it is not common.
As you mentioned, you are going to withdrawal from this medication with the help of your doctor. That is the best way to go off fluoxetine. Otherwise, if you stop the medication right away, you will experience headaches, dizziness, anxiety and pins and needles sensations.
Withdrawal needs to be slow, taking a little less medication at regular intervals. This is not a medication that causes dependence so if you do experience side effects from withdrawal, they will be temporary. The medication stays in your blood for a few weeks after you stop taking it, but it naturally decreases as time goes on.
I hope this has helped you,