Please don't think me rude. I just wanted to say - are you sure all your data is gone?
The reason I mention this is that the Health app has become so multilayered with heaven knows the number of options, sub categories and so on.
When I first opened it, I was asked if I wanted to create a new Medical profile (or words to that effect). I said "No", reasoning that this might overwrite what I already had in there. Could this have happened to you??
Assuming you ignored this, as I did, then your data may still be there. I literally spent a good 5-10 minutes getting to grips with all the features and, sure enough, there was my data - tons of it spread over different categories. Not all in one place.
My suggestion is that you set aside a nice cup of tea and plenty of time in a quiet room; and thoroughly investigate this complex app
Ian