@Cindyloohoo,
I'm guessing you're being OCD about it but get a pregnancy test and find out. They're not that expensive.
And, you might want to contact your doctor and ask about the Melatonin thing. And, really, tell him or her any herbal supplements you are taking, no matter what they are and no matter what they are for, as they can affect not only birth control efficacy but any other drugs you may be taking, or your blood sugar, etc.