Severe cramps

I had a reallly rough night. Last night I had lower back/tailbone pain. I woke up around 12:30 am with severe cramping. We would have gone to the hospital except I felt like I couldn't walk, it was the worst pain I've ever felt like strong period cramps. It came in waves, my legs were shaking and it was awful. It stopped and got better after an hour. During this there was only light pink blood when I wiped but no other bleeding. I am 5+3 and going to call the dr today, but I am so scared. Has anyone has this happen before and ended up being ok? :(