Apple Watch suddenly stopped sending Sleep data to iPhone

I have Apple Watch series 6, just updated to 11.3.1. And and iPhone 13 Pro Max, also just updated to 18.3.1. Before the updates, my Watch about 6 days ago just stopped sending Sleep data to the iPhone. First it sent a little, and now, nothing. This is all before I downloaded and installed the updates yesterday, which I hoped would fix it, but no, it is still happening. Long ago, I turned on, in the Watch app, "Track Sleep with Apple Watch." Is there something else needed?? I swear, before it stopped sending data, I had not changed a thing. I really rely on my Watch to track my sleep, so please help if you know what is happening.