What is going on??

Crystal • 24 TTC #1 for 3years. Hubby is diabetic && has retrograde ejaculation.
Why does my BBT chart look so off. Its up and down. I take it at the same time everyday && I take it vaginally. There's so many dips and rises. I don't temp while on my period BC I do it vaginally. Aug. && Sept. Charts. Please if you have any ideas let me know.!!