I Had A Severe Case Of Food Poisoning, Lasting 6

I had a severe case of food poisoning, lasting 6 days. I now have severe headaches that nothing will relieve, dry mouth, left side flank pain and blood on the toilet paper after urinating and in my urine (urine test confirmed). I only have one kidney on the left side, the right kidney was removed. I am also extremely fatigued. GP suggested dehydration still, but when I do urinate it is quiet clear. Would I still be dehydrated or is there something more?