more likely that you just haven't ovulated since you are feeding more again, you likely knocked yourself into being anovulatory. Usually when your fertility returns while still breastfeeding it is NOT regular. Some women can spend months in between periods.
Id trust the tests... breastfeeding will NOT make a positive test show up negative.
Artist, photographer, stay-at-home-mom and Marine wife. Mom to 4; a boy and three little girls.