Late period by 4 days, now horrible pain

I was anxiously awaiting my period and had taken a hpt that came back bfn. I finally got it about 4 hours ago, at first just slight cramping and light blood. Now, my severe pain woke me up out of a deep sleep. I've been doubled over for over an hour, these cramps are like nothing I've ever experienced. I'm bleeding, not a heavy amount, I would say more than just light spotting, a moderate amount of brig red, watery blood. I'm used to seeing very tissue heavy, darker red, thicker periods and have never been in this much pain. Any similar experiences or advice would be awesome. 😔