please, i need some help i cant tell if im pregnant!

in sep i got my period on the 11th and it lasted its normal five days then in oct i got it on the 7th and again it lasted its five days. on the period app i was supposed to get my period on the 4th of november but i had sex oct 30th i think i was stressign so i missed my period becuase thats happened to me where i missed my period for three months. but when i mised my period for 11 days i then took a home test that was negative and calmed down a little bit and got my period nov 20th aroudn the same time my mom got hers. and it lasted 5 days and was its normal heavy period that i usually have. i did so  research recently and heard that some women have their periods in early pregnancy andthey dont get postives until 3 months later. i took a test in the morning two days ago nad again negative. i dont have any symptoms to much maybe one or two becuase im freaking out a little. but is there a chance im pregnant? and is it common for women to be pregnant and have their periods?