Help something is wrong with my turtle?

we have had our turtle sammy for about 8 years...the past 3 days he wont eat and usually when i touch his back feet he will pull them in now he dosent move them at all he stays in his little hut all day and night...he is a tortis so we only give him water about once every 2 weeks so i put him in the sink last night and let him enjoy that but he just went right back to his hut...is he just being a turtle or dying? is there a way to tell if he is sick?