I Had Unprotected Sex On 19th Of January And Took

I had unprotected sex on 19th of January and took postinor 2 the next day. My period ended on the 3rd of January. A week after I took the pills, I started having spottings with brown color but little blood it gets lesser and lesser day by day. On Wednesday 3rd February i started to bleed like how a period should feel n look like the texture, thickness and color. I started to take Diane35 on Thursday as I dont want to take postinor2 anymore. What could this be? Do you think this is normal or should I see a doctor?