Hi ..I know it's been awhile since you posted this but did you ever get an explanation? I am on Zoloft and have not changed my meds and have been having serotonin withdrawal symptoms for no reason. I'm getting worried. I phoned the pharmacy and asked if the meds they gave me could have been expired therefore rendering the med ineffective but they said the bottle did not expire until 2026. I'm at a loss and scared.