Why My Breasts Are Lactating And My Period Is Late?

hi , my name is gabrielle. I m having a pregnancy scare I have taken home pregnancy test after realizing my period was a week late and they were negative and I ve also had my prolactin levels tested and they were normal. my breasts are lactating and have been for a while what could this mean? other symptoms I ve had are tiredness, weird cravings, headaches, dizziness, cramping, constipation and itching breasts