Uhm.. A little help?

Ive had the nexplanon since august 2018. My boyfriend and I had unprotected sex on the 1st and on the 2nd we began some intense workouts. Yesterday i started bleeding again and ive been experiencing some nausea and diarrhea. I think it's my period, but it just ended on the 29th. Could it possibly be my period since ive changed some habits of mine??