weird period, kinda confused.. help

I started taking birth control 2 and a half weeks ago while on antibiotics for the first week, between those 3 weeks i had unprotected sex and then missed 2 days, the next day i started lightly bleeding light pink blood and then it went to a normal period for a day, after that i’ve just been barely bleeding throughout the day and its now been a week. my periods are usually 3 days long and then done. i’ve never had one for a week long and i don’t understand why i am now. could it be from the birth control i just started taking?? anyone experienced the same thing?