side effects of ranitidine hydrochloride

I am a 65 year old woman. For the past month I have been taking ranitidine hydrochloride (150mg per day) because of an acid reflux problem which reponded quit well to that medication. However, three weeks after starting this treatment I began experiencing severe diarrhea, minor dizziness, and feelings of malaise and periods of rapid heartbeat. Do you think these are side effects of the ranitidine hydrochloride medication?