New to Birth control

I went on birth control recently for period purposes. I had one week left on the second packet when I noticed I was bleeding brown/red fast forward it’s coming up to 4weeks/ 1 month. But this weeks gotten kinda worse it’s more red blood no more brown. I’ve been to the doctors the told me to keep taken the pill like usual. Why am I bleeding sm isn’t the pill supposed to stop periods?!

I’m on rigevidon and my gp/doctor recently told me to continue my 3rd pack which had 21 tablets. I can consistently take them or have a break once a pack or every 3 months I had a lot of options. I’m just concerned about bleeding while on it but apparently it’s normal and can take 3-6 months for my body to be used to it