Hey,
I am 35 years old, and I was diagnosed with moderate to severe sleep apnea about 5 years ago. My wife of ten years now had always complained of my snoring, and how bad it was. Finally, I went to the doctor about it, and I did a sleep study. I went to a place where I was watched while I slept to see if anything happened. Turns out, I stopped breathing over 30 times an hour. Normal is considered to be only 2-5 IIRC. At the time I was about 225 pounds, which put me at obese for my 5'7" size.
My doctor suggested some surgery to remove my tonsils & adnoids and shorten my (very long) uvula (hangy-downy-thing in the back of your throat). A positive side-effect of the surgery was not wanting to eat much, which healped me lose 25 pounds fast. My wife was amazed at how much better my snoring was - it was gone! There were times when my wife would be so worried because she couldn't hear anything at all... lol
I started to gain some of the weight back, so I really took to eating better and excersizing. I got down to 165 pounds, and I felt great. I had a lot less problems with my back, I slept so much better, and I had a ton of energy.
Unfortunately, over the past two years I've put the pounds back on, and my snoring (and back trouble) have returned. I'm trying to excersize again, but it's harder than before.
Anyway, that's my story of sleep apnea. I would recommend seeing your doctor and getting checked out. It could be sleep apnea, ADHD, or even a case of mild depression. There are so many possibilities that it's hard to say for sure. A little (or a lot) or trial and error may be necessary with you and your doctor. Patience and time will work things out. In the mean time, it's always better to try to eat right and excersize, and get a solid and regular amount of sleep every night.