I'm Always Fatigued..have Had Blood Test For Iron Deficiency..checked Ok..had

I'm always fatigued..have had blood test for iron deficiency..checked ok..had blood checked for he c..checked ok..have OA..and restless leg..what else could be making me tired..I drink plenty of water..get 6-8 hrs sleep..5'10" and weigh 170..pretty physical job..has thyroid checked ok..what else should I check?