Apple Watch “All of a sudden“ not syncing with Apple health app on iPhone 7 Plus

I have Apple Watch Series 3 an iPhone 7 Plus. Our use the Apple Watch to track exercise in steps. I actively use Health app and activity app daily. All of a sudden yesterday, my step stopped recording to the health app and activity app. The steps show on my watch, but nowhere else. When I tried to add the steps manually to the health app, it would add it and then I would come back later and it would be gone. I have followed previous posts advice to turn off my iPhone and Apple Watch after closing related apps to my Apple Watch. I restarted my phone first then the Apple Watch. Still nothing works. I do not want to totally reset my Apple Watch or iPhone 7 Plus because I do not want to lose all my historical data. Why is this happening all of a sudden? Is anybody else having this problem ?