period almost a month late !!

i’m on birth control i have three weeks white pills and the last week is when i usually start.. i have been having a lot of unprotected sex. but i’m on my first day of my red pills and i’m having a dark brown discharge a lot of it kinda like i’m on my period but i’m not sure bc it’s usually not dark brown from the start idk maybe i’m over thinking i just wanted someone’s else’s opinion on it !!