That seems like a pretty good indicator of an adverse drug reaction! Please contact the drug manufacturer if this turns out to be the case. Don't count on your doctor to do it; do it yourself. The manufacturer should be on the bottle; if not, ask the pharmacist.

Quite often the pharma industry doesn't know about ADRs for a long time since they count on doctors and patients to report them.

(Disclaimer: I work for a drug company.)