sex on last day of period

Taylor • 06/09/2018💍 09/21/18👦🏼💙 02/03/21👶🏼💕
I just had sex and I just got off my period I think, I'm still spotting the brown stuff like at the end of the period, but he came in me and I'm not on birth control, and my friend told me it wasn't likely I would get pregnant. My period lasted for 7 days and it's 28 days before I get another one. Is this true, if not please educate me 🤞🏻