Yesterday I Came Over All Dizzy And Was Sick Twice,

Yesterday I came over all dizzy and was sick twice, my legs were like jelly. I have spent most of today aslee I am so tired but not been sick again , my legs still feel like jelly though .
I do suffer with lower back problems and restless leg syndrome , is this all connected to how I am feeling .
My job is in retail and on my feet a good 9 hrs a day and can walk up to 7-10 miles a day !