I'd say it would be the pregnancy dear. DH recently said I have started to snore but I don't believe him... He has been snoring really badly for the past few months and I hit him to tell him to roll over and I think he wants something to whinge about so I don't do it anymore. I caught him out the other night as he said I woke him up because of my snoring, but I was wide awake at the time!!!
I really wouldn't worry about it, wait until after bub is born and your baby weight starts to drop off, then you'll know if it is the preg (which it is! )
Take care... Come on Nudger, time to make an appearance!