12 week old refusing to eat

My baby girl had been doing so amazing with breastfeeding & all of a sudden she is screaming at breast and only eating for a few minutes on one side every few hours. I’ve tried different positions and swapping out the pacifier, but to no avail! She sucks on her paci fine so i don’t think it’s her gums.... I just don’t know what to do!!! She has about 4 wet diapers a day, and when she cries she has tears so I don’t think she is dehydrated but i also don’t want it to come to that either..