implantation or period?

my boyfriend and i had unprotected sex and he came in me on multiple occasions, i’m unsure of whether or not it was during my fertile window. since then ive has symptoms like huge swollen boobs (that i dont really get from pms), extremely tired and just feel pretty off. my period was supposed to start today and usually i have bright red blood right off the bat, but all day its been very light and just this pinkish blood. could this be implantation or is it more likely this is just a weird period? i’ve never really had this before. it was a light flow of this stuff for about an hour and now nothing except when i wipe. i have slight cramps but i’m also constipated so not sure which cramps are which 😂 please help!!