Hi, I can understand your concern regarding your symptoms and the side effects. Mirtazapine (mirtaz) is a n effective drug for depression and anxiety. Since its already three weeks on this drug, a review of improvement would be warranted and accordingly dose can be increased for further improvement. You can discuss regarding this with your psychiatrist. Some of the common Mirtazapine s side effects includes sedation, weight gain, increased appetite. Monitoring of liver function and blood counts is usually recommended. You should start some physical activity regularly which will help in countering the weight related side effects as well as help in controlling your symptoms as well. Hope this information was helpful. Best wishes.