Hi, thanks of using health care magic
You may want to consider speaking to your doctor to find out whether there are any other anxiolytics that may be effective for you.There are some that are weight neutral and others that promote weight loss
. This may or may not be an option.
If you are on other medications as well , they may or may not be contributing to your weight gain , even antihistamines can result in an increase in weight.
There are different dietary options available, you have tried the low fat low calories option, you can consider trying the low carb diet and see if the results are any better for you.
Remember that because you are working out in a gym and with a trainer, you may be gaining muscle mass while you lose fat, which would contribute to the numbers that you are seeing.
If you continue to find it difficult, consider visiting a bariactrician.
I hope this helps,