Watch sleeping app

Make sure you are looking at the day (D) tab on the results and you should see this kind of graph.

If you don't see it but you do see totals of time asleep, then I have no idea why that is the case.

If this does not help contact Apple Support or wait for someone else to respond.

Go to your iPhone and look in Health app, browse tab, Sleep. For each day you used the Sleep app there will be graphical results. You will not find it on the Watch.