7 weeks postpartum and spotting

Okay so I am 7 weeks postpartum bleeding stopped at 5 weeks and all of a sudden for the last three days I have been spotting I breastfeed but supplement with formula very seldomly could this be my cycle trying to return or just spotting from breastfeeding it's bright red in color but is not consistent on a pad but is there when I wipe any input would be nice thanks