Often, though, it's not the chemical imbalance (no offense, but this theory has been overblown out of proportion)... so I think it's worth trying to explore what can you do. Meds are not gonna help your cognitive patterns. If that doesn't help, you can see a psychiatrist, or your psychologist can refer you to one.

(where I live psychiatrist hardly ever go beyond "here's your script, NEXT!". If you can find somebody better with wholesome approach that's great, though).