Help re calendar wiping clear :-(

Kim • Stay home mum of 1 and so inlove with my best friend/soulmate.
I dont know what happened but my calendar for october went blank and all the details eg cycle length. Fertility etc n now November has changed as its going by previous cycles that changed. Its all messed up now so is there a way to re enter octobers cycle to correct my info as now its all wrong :-(