I Am Diabetic. Age 52. I Try To Stay Active

I am diabetic. Age 52. I try to stay active most of the day but as night draws near my legs from my knees just ache and hurts. It wears me out! Heat helps it like covering them over with a blanket. I do have arthritis in my knees. Concern me! I also try to wear good support shoes but they ache and hurt so bad that at time it makes u stomach at ur stomach. What could it be? Thank u