Have you completed the troubleshooting listed in the thread, such as holding down the power button for more then 7 sec or resetting the watch?
do you see watchface?
than it could be the water saving mode is activated. you should do it before swim and shower....
you need to press the on/off button for longer and it will be text message shown and mode is stopped.
there is a shortcut button in setting like a raindrop I touched it one time without knowing that... And I had same problem as you.
Hope really that you only activate this.... and your watch works normal after stopping this...