What Causes Fingers And Toe Numbness With Spinal Pain?

i am an sle patient and my spine keeps hurting specially in da back of my neck and i am having a big problem falling a sleep for the past one year i have been tryin to get pregnant,no such luck and six months ago i got diagnosed with sle,sjgorens syndrome and rheumatoid arthiritis,i am put on medixon 8mg and depression pills,my fingers and toes have this lifeless feelings,why?