My BBT chart is odd

A
Hi all,
We've been TTC for 4 cycles now with no luck. This last cycle ivrbeen charting my BBT. I started just before my last period and according to my apps my next period is due within the next 3/4 days (depending on which app you look at!!)
I was told that fertility friend is great for charting, so in out all of my periods and temps (I'm yet to add in all of my other data) but the app is now telling me that my temperatures are all over the place which isn't normal!
Anyone else have a chart that looks like this? I'm not sure if I should go to the docs or not?