Last few cycles had pink & brown spotting 2days before period (cd24). next day, nothing. next day full flow(cd26). which day ends my luteal phase?

Prob CD 26 : There is not really a way to know the exact answer but i would count the first day of full flow. How does knowing the end of your luteal phase help you though?

Variable: The luteal phase ends when Progesterone production from the ovary drops if pregnancy does not occur. Usually this occurs with the onset of what a woman knows is her period. Premenstrual spotting may indicate slightly low Progesterone levels during the luteal phase.