Brown Period

A

I have been on my period for the last 4 days and it has been dark brown the entire time. There is no way I am pregnant and the only it thing that has changed in my life was I was taking antibiotics for a yeast infection and BV the week before my period came. Everything else has been the same , same cramping , headaches, other symptoms. Could that be a reason for the change in color or the blood? Should I be concerned ?