I got my new watch active on release day but have only just started using it at night to track my sleep. I've noticed on 3 or 4 occasions that the watch is marking me as asleep while I'm sat relaxing watching TV! I can be using my phone or even using the apps on the Watch but it is marking me as asleep! Apparently I've already had 3 naps today! It's throwing out all my sleep records! Any ideas on how to fix it?