I Took A Melatonin On Tuesday Evening, Did Not Read

I took a melatonin on Tuesday evening, did not read the directions on bottle , since then I feel down mot myself and I have chest pains. What can I do. I have tried to get in touch with my doctor and no answer. Please let me know what to do , I am also on blood pressure pills, has that got anything to do with the way
I an feeling. emails address, YYYY@YYYY