Pregnant or Pill Adjustment

So my period ended on the 24th of April now May 2nd i started spotting but 2 days before i could barely get through my morning shift so much cramps and stiffness in my chest and abdomen i don't know what is going on and i am on a low dose bc pill i missed a few and stared back could that be the issue my body is so sore has anyone experience this before and I'm having headaches here and there