Sleep not being tracked correctly

[Jayleerod210]

Past few days my watch has not been tracking my sleep correctly.I've tried restarting watch and it is up to date.what could it be?

Moderator edit: subject updated for clarity

[Jrdubyakc]

A few things that can affect sleep readings (according to fitbit):

"There are a few scenarios where you might see your sleep pattern (which shows your time asleep, restless, and awake) instead of sleep stages:
If you slept in a position that prevented your device from getting a consistent heart-rate reading or wore it too loosely. For best results, wear your device higher on your wrist (about 2-3 finger widths above your wrist bone). The band should feel secure but not too tight.
If you used the Begin Sleep Now option in the Fitbit app (instead of simply wearing your device to bed). For more information on automatic sleep tracking, see How do I track my sleep?
If you slept for less than 3 hours.
If your device’s battery is critically low."

Any of these explain the issue? 

[Jayleerod210]

I simply wear it to sleep as I always have.Battery fully charged.I sleep more them 6 hrs.as I normally do.Was reading fine up until a few days ago.It will say I slept 3 to 4 hrs when I slept more then that.I will try tightening it maybe that could be it.