What Causes Sleepiness?

35, 5'10'', no past medical issues. I am always sleepy. I will fall asleep sever times throughout the day even after 8-10 hours sleep the night before. When at work the social interactions are difficult because of the groggines and it feels like im zoned out, like im out of focus. Construction is dangerous as it is so sleepiness on the job could one day result in an accident. When im laid off(Boilermakers get laid off as a part of the job) the problem is even worse. Im too tired to do anything so my wife and daughter both suffer and so I continue to get heavier as a result, this worries them. I have taken an Adderall before, about two months ago from a friend with ADHD. He said it was prescribed for people with Narcolepsy too so i gave it a try and i didnt get hyper and all strung out but I did feel more alert. I will not take anything illegally both because i think it to be immorall and my employer does random drug tests. So in an attempt to actually live my life and be a more active father and husband I am reaching out to you for help. Can you help?