Flagyl

So as usual I did some research I recently got my first Pap smear and found out I had BV. They gave me an antibiotic and prescribed me Flagyl. This is my first day and I’m a lil worried because my boobs are hurting bad and my mood is out of control today and I was wondering if that’s normal or maybe I’m getting my period? I haven’t had my period for 6 months but they haven’t informed me about that I was worried about the BV at the moment. And also will I get a yeast infection after I’m done with the Flagyl? Will it be coming back shortly? How do I prevent it?