Sleeping, or really not being able to

I am over 16 weeks and I have trouble staying asleep.  I go to bed at about the same time every night and sometimes sleep through until the morning.  Other times I wake up thinking it is morning only to find it is 0100-0300 in the morning.  I can't go back to sleep and I wake up  "feeling" like I slept for 8+ hours.  I don't Nap throughout the day, even though I can if I wanted to...I am just not tired.  I have taken 2 naps total since my BFP.  This is my 3rd and this never happened with my first 2.  Frustrated cuz I just want to sleep.  Please tell me I'm not alone....lol.  It's currently 0200 where i am and have been awake for about an hour....grrrr.