Can't change incorrect period

Back in October 2018 my gp gave me medication to force a period as I hadn't had one since January 2018 and I logged this on the app.

This was my last period

In December I had spotting for 1 day which I logged mistakenly (under spotting. I never clicked that my period had started!) then realised it was because me and my SO had had sex 2 days before and sometimes I bleed from this over the following few days if we've been a little rough.

I have deleted the spotting from my log yet the app still wants to tell me that this one day of light spotting was a period no matter how I try delete it so all my future predictions are completely wrong.

How do I fix this please?

Iv already tried deleting and reinstalling the app but it picked up all my old info without me asking it to. Iv tried turning off predictions and turning them back on too.