Tudor Black Bay power reserve

[Kryptofresh]

Hey guys, my Black bay Noir power reserve is acting odd. I wear it every day, and take it off before going to sleep. Even though I wear is every day, it seems to stop keeping time by the time I wake up (usually 8hrs of sleep), has anyone ever experienced this ? Furthermore, I decided to run an experiment by winding my watch before sleep and not wearing it the following days to see how long it would run for (came to 36hrs and 46mins). The watch keeps time accurately but won't store power for long, i'd appreciate any feedback if you have had a similar experience.