What are the ingredients? My guess is that it wasn't good for you in the first place, probably full of sugar and stimulants and lots of artificial ingredients that may have unwanted or unhealthful effects. Nobody needs a supplement to go the gym. Unless you want to look like The Arnold, but then you have to face his kidney problems etc.
I do not know what the ingredients are for that medication but if there are stimulants you need to be careful because zoloft also has a stimulating effect and the two together could be harmful. Check with your doctor.
This doesn't answer your question but I would be looking at making behavioral changes versus depending on some drug.
Maybe psychotherapy to address other issues could be of use. ??
The doctor has a website (shrinkyourself.com) that you may be interested in.