help

hi just wanted to get some advice on what this could be...hubby and i had a baby 6 weeks ago we didnt wait the 6 weeks to have sex...i took two pink dyes and they had faint positive lines and a blue dye that was negative....well i started spotting light pink the next day it got heavier and darker but was still light didnt even fill up a pad and faint cramps...and ive had nasuea for a few days.. could this be my period returning or implantation!?