Lower Back Gets A Pain And Then I Feel The

lower back gets a pain and then I feel the pain going down both, it feels like they are going numb. I have to immediately lay down where ever I can. By the time I finally lay down the legs are numb, and it feels like can not walk . Yesterday, it happened twice, no sooner did it stop and I started to get up and it happened again. Do you know what this is?
Thank you, Judy Nadler