Mylan Birth control pill.

Hey all, I started a new birth control last month, haven't noticed any symptoms until recently. I believe. I had a period and it came early and ended early, was light to medium the whole time. Then a few days after I thought I had stopped, I start to spot. I'm like "okay, thays annoying" but it's lasted about four days and I'm assuming I'm having another period? Is that normal? Should I be worried? If not now, then when should I worry?