it does sound like diabetes ecspecially the sleepness after eating. being over weight does not always mean ur diabetic. I would buy a a blood glucose meter and monitor you blood sugar for about a week usally 3-7 days take your blood sugar before u eat and an hour after. low blood sugar is 79 and below high blood sugar is 120 and up. this way u can tell what your doing and if ur sugar is low drink OJ or some other type of juice or soda. if its high but less than 250 drink about two bottles of water and walk alot. (take stairs instead of elvator) if higher then 250 seek medical help