Period one week early, spotting one week after period ends

Patient: I am on the pill and have always had regular periods that come at around this same time every month. This month, my period came week early. In the week that I was supposed to have my period I started spotting. This has never happened to me before. I have not gained or lost weight, my diet is normal, and I have not been any more stressed this month than I usually am (I’m a PhD student). What’s going on with my period?