In the F-droid archove there is also “Migraine Tracker”. It can be used to track “episodes” (migraine or whatever) in a very easy way.

Maybe you can revive it or fork it and update it easily to avoid the vulnerabilities that made them fall down from the “normal” archive.

https://f-droid.org/wiki/page/com.rhiannonweb.android.migrainetracker