And, if a period journal wouldn’t work, I use an app called “Clue” Very helpful, and it “predicts” (not always accurate, don’t think you can be 100% accurate) when your next period will happen, how long it’ll last, etc. The idea is that if you put more data and the longer you use the app, the more accurate it will be.
Also, a great way to keep track of symptoms. Cramps, bloating, hot flashes, etc. Then you can see if a symptom is normal for you, if you’ve had it before, how long, it’s a very helpful app. A little annoying on the notifications but that’s just me.
here is a link
Open on phone to download, or on computer if you just want to read info