Weird chart

This has been the strangest chart i have ever had. Mine are usually pretty similar but why a big drop on 12dpo and a big rise on 13dpo. Never experienced this before. My bbt is usually down by the cover line at 13dpo if i'm not pregnant, but i'm not ready to test again. Got a bfn on 11dpo. And with the big drop on 12dpo i thought for sure i was out. Not sure what to think anymore. Is it just a waiting game at this point? More freaking waiting :(

I just want my double rainbow baby.