After period pains

My period was 3 days late (I’m normally very regular) and the bleeding was slightly different (lighter in colour and flow) but I didn’t think anything of it at the time. Now a week later I am still experiencing cramp like pains/heaviness and nausea and they don’t seem to be going away. Should I be concerned about this? I do get bad period pains and the last bleed was more painful that usual, I also get ovulation pains however have never experienced this.