There are so many possibilities of what it could be...thyroid, diet, depression, chemical imbalance, vitamin defficiency, etc. I had the same problem of wanting to sleep all the time. I would fall asleep on the way to work, at work, on the way home, sleep for 2 hours after work, eat dinner, then go to bed. I never wanted to leave the house or visit friends, because I'd rather sleep. It started when I was 22y/o. I had a sleep study done and it revealed that I have idiopathic hypersomnia- which means excessive daytime sleepiness, but they don't know why. Not quite narcolepsy, because I didn't loose muscle control or dream during the nap study, but something like it. I'm not a big fan of taking meds, but I literally can't function without them. Caffeine had no affect on me at all. Now I take 3 pills every morning, which will keep me going through the work day. It's not a cure, but it made my quality of life so much better. After I had my daughter, I tried to stay off the medicine to see how I would do...result, my boss thought I was severely depressed and hated my life, because my eyes were always "sleepy" looking and I had trouble focusing. After I started back on the medicine, she couldn't believe the change she saw in me. I was happy and cheerful, alert...
Definitely do the sleep study- not only for you, but for your family too. Don't let life pass you by anymore. It's an annoying process to go through, but so worth it in the end. Be open to what they say and suggest.