Birth control?

Meghan • Im the artificial redhead.
So I'm not really sure what's going on with my period.. like I started yesterday then stopped and the blood I had would be like the blood when you are ending.. so I started my birth control today as I have had cramps and I did bleed yesterday. Was This incorrect of me to do so? Because my doctor said to take it the Sunday after you start and I technically would have started yesterday but as I said before, my flow as stopped since yesterday and the blood was as if I had just ended, even though I had not yet even started. I'm kind of scared that I did something wrong and have possibly hurt my body because of this.