Hi ladies new to the tracking of BBT and I’m confused as the app is saying different to my BBT chart. App is saying I ovulated on 25th Jan but chart looks like 20th Jan?

I was using OPK strips but of course I ran out of them literally the day I was due my peak. Ive ordered some more but just wondered if anyone had any insights as my DPO could now be wrong. I’m going out of my mind with this TWW and have all my fingers and toes crossed TTC # 1 I’ve never been pregnant before so don’t even know what symptoms I’m supposed to be having. BD to all 💛💛💛💛