How old is your little one now? She must still be very young? It is more likely that your headaches are related to the birth and will ease up as you recover. Is this your first baby? How did the birth go?
do you see a chiropractor? Might be worth a check up. Do you feel comfortable when you are breastfeeding? Are your nipples cracked or grazed?
Even in rare cases where hormones cause headaches, levels even out over the early weeks so this is unlikely to persist.