Question about sciatica??

A few days ago my left foot started hurting on top and on the side near my ankle. The pain has steadily progressed these last few days and now my lower back, left thigh muscle and lower calf are hurting. About 1 year ago I was tested for lupus. I did have positive ANA but the titer level for lupus was low so my rheumatologist ruled out lupus. The muscle pain and joint pain is becoming wide spread but I mostly feel it in my back and it is driving me crazy. Could the sciatic nerve cause this kind of pain? I don't see my rheumatologist until the 27 of March so I am kinda dealing with the pain but I am starting to limp when I walk because of the pain in my foot that radiates from my lower back.