Watch Apps Dissapeared

Was using my watch - left it on charge, came back and many basic apps such as Calendar and Weather have disappeared. I have powered it off and on again and this has not seemed to work. I have also tried to re-install the apps on the Watch App Store, but it says it requires an iPhone - despite definitely being connected!

I haven't tried to erase it yet - but I don't want to do that unless there is no other option. If anyone has any ideas on how to fix this it would be very helpful!