Hula hooping causing numb feeling; what shall I do?

I received a 6 pound weighted hula hoop with ridges on on it for Christmas and I have been using it almost daily ever since. Just a couple weeks ago, as I was hooping, I felt a sudden sharp pain, as if the hoop hit a nerve or something, on my lower left waist, and then where it hit and the surrounding area, went numb. I instantly recoiled in pain and dropped my weighted hula hoop. I was nervous and afraid of the numbing feeling and tried to get some feeling and circulation in that area by rubbing and massaging it. That area was numb for a few hours before I regained feeling there.

Ever since then, I was afraid to use my 6 pound weighted hula hoop. Just today, I decided to try it again. And about 10 minutes into my hula hooping exercise, the same area went numb again. But this time, it slowly went numb without any instant sharp pain.

I really enjoy hula hooping, but it seems that it might be advisable to discontinue using my 6 pound weighted hula hoop. What shall I do? Any ideas of what happened? Any recommendations or advice would be much appreciated!