Period or Spotting???

Ok so I’m a few days late which happened last month as well, since I only just recently started using the pill. I was supposed to start and I started getting a bit of the painful cramps, and the tender breasts, along with some headaches and lightheaded ness, and what I thought was my period. The only reason I say thought is because compared to my usual crime scene heavy flow filled with clotting, it’s been significantly lighter but much darker. Is this a normal change once the body gets used to the pill? I’m just wanting to absolutely make sure it is my period