Need answers please

So i had a copper iud for almost a year & got it removed in December .. well my husband was away on work trip and he came home and we obviously ended up having sex so these were 4 days in a row multiple rounds no protection. I got my period directly after that but it was different than my normal periods only lasted 5 days and mostly brown blood, well fast forward to a week ago i went in to get on the pill, the lady said it would take a full week to get into my system well i also had a whole week till my period was due. My last period was 1/21-1/25 i got my bc pills 2/13 they didnt kick in until 2/20 and af was due the same day the pills became effective 2/20 so now i am 4 days late on my period and was wondering if there is any way i could have possibly gotton pregnant before the period and that is why i am still late? Ive had a few symptoms like soar & vainy breast and nipple darkening but not sure if it's related to me getting used to the hormones of pills or am i pregnant?? Im sorry for being confusing basically im just wondering if there is any sort of chance or if im just overreacting

++ forgot to mention we havent had sex since 1/18-1/20