I remember when I was that far along I slept soooooo much. I didn't know why though because I had only been about a week late on my period. For the next 3 weeks if I wasn't sleeping, I was up eating something. I didn't eat a lot, but enough to make the nausia go away. I thought I was actually coming down with the flu, but I was about 5/6 weeks preggy....
So what you're going though is totally normal. I read that the reason why we sleep so much in the beginning is the actual work it takes the body to reproduce is immense. The body actually releases a hormone that makes us extreemely sleepy so that the body can use all of the engergy to create your angel!!
Good luck with your pregnancy!! The sleepiness shouldn't burdon you for too much longer...Enjoy it while you can I guess, cuz 2 is gonna be a whammie!!
Sarah