Period change? Idk lol

So normally my periods are 6-7 days.

This time, I’m only on my third day, and I’m already lightening up like I do towards the end of my period.

I took 8 expired birth control pills around March 17th, lol hoping they weren’t expired, and was trying to replicate the effect of Plan B based off of a chart I found online.

But since they are expired, I assumed they wouldn’t affect my period.

Is that what this is? Lol why am I bleeding less?

I’m happy about it cause I don’t like week long periods obviously, but I just want to understand why it’s changing.

(Btw, the blood has been normal color. Not real pale pink red. It’s been old blood and bright red with some clots, so it’s not implantation bleeding. Was I just blessed with a short period? Lol)