What Causes Sudden Numbness In Legs Along With Severe Headache?

Hi there,I get so that I loose the complete power in my legs & arms & I also get bad headaches. Sometimes it s behind my eye or at the back of my head . It is very frightening for me It doesn t happen all the time but the last year it is happening more & more. I am 64 year old woman. Can you explain what is happening to me?