Help! Period while on progesterone ?

Mil

I had an <a href="https://glowing.com/glow-fertility-program">iui</a> on 22/6 and was put on progesterone after. Had majorly light spotting (like mixed with CM) yesterday that went away just started again when wiping brownish in color. AF is due today, so I'm not sure. Also had read that AF can be delayed until you stop progesterone. What do you guys think?