Period for 10 days

I started my birth control on the 3rd, and was supposed to have my period that same week if I wasn’t on it. I took my pill like an hour late than normal on the 14th and then ended up getting mild cramping on the 15th and then some light bleeding, and I’ve been on my period since then with decently medium bleeding everyday. I just started my placebo pills today. I’m not really sure why this is happening, I just started my placebos today. Will it stop?