The teeth grinding is defo causing your headaches, after someone mentioned it to me I also realised I had a bad habit of biting my teeth together, say when I was peeling potatoes or other times when I was standing in one spot. As for the tiredness all the time, I did use to stop breathing in my sleep, only for a nano sec but enough to wake me, well I wouldn't wake but it was enough to disturb my sleep! It turned out that the dangly thing in my throat was way to long! (you know the thing you see that looks like a little tongue hanging down when you look in your throat?) Its worth a mention to your GP :)