I was using it as a lookup source. I did have intermittent access to WiFi, and I synched quite regularly. So I shouldn't have lost any new notes that I might have created in the period before I cleared my cache. (Even if I did, that would not have mattered much, because such notes would have consisted of quotations or additions to my reading wish list.) What I am frantic about, is the stash of health and administrative info that I've built up over years and which had survived a few migrations between cellphones without any hiccups.
The problem was that I had forgotten my camera at home so I had to use my phone's camera all the time. The memory ran out and for various reasons I could not transfer the photos to another device or memory card. So I cleared all the cached data that I thought had been saved someplace else than on my phone or its SD card.
On my return home, I could not log into Evernote because the app still would not open, so I uninstalled and reinstalled it. However, the startup screen offered only a choice between signing up (i.e. as a new client) or signing in via Google, so I chose the latter option to avoid creating a different Evernote account. (Have never tried using Evernote Web before; always used the app on my phone only.) But I had trouble remembering my Google password, and after entering and re-entering my password and eventually changing it, I decided to risk opening Evernote by means of the 'sign up' option (instead of via Google). I ended up creating - exactly as I had feared - a different Evernote account (other e-mail address than the original one) with a new password . Eventually I discovered Evernote Web in the course of a desperate web search, and I accessed the account created that had been created with my original e-mail address and password. That should have led me to all my data, but it is empty! The app treats me as a new customer who had not entered a byte of data before.