Period Blood Changed in Color

Hi! For some reason a few months ago, my period changed in flow and color, it used to be really bright red and heavy but it changed to a more dull red and not as heavy. But for some reason, today its back to the way it used to be.

When my period changed I was pretty confused because the color of it looked like how my periods used to look during the last few days, a dark red (almost brownish red). I kept having periods, 3 or 4, with this new dark color of period even on the first day of the periods.

I’m pretty happy about it going back to how it used to be because this was my normal, I guess. I’m on birth control (enskyce progestin and estrogen BC pill) but I’ve been on it for 2 years so idk if it has much to do about something that only changed a few months ago. The flow only lessened a little bit and my periods still came right on time. But if anyone knows what the change in color might mean, please share your knowledge. Thanks!!