thrush?

Baby is 3 weeks old, almost 4 weeks and has breastfed the whole time. She does not have the best latch, but I manage through the pain most times she's nursing. Recently I've noticed she has the white film on her tongue and my nipples ache and I have random pain inside my breasts. Is this all because her latch isn't good or could it be thrush? What are you experience with thrush? What did it look like on your nipples, in babies mouth and what did it feel like? (I've tried to get her to open her mouth wide to get a better latch but she usually just has the nipple in her mouth. Maybe a tiny bit of areola but not much at all) I don't want to give up breastfeeding but it's starting to be a lot! Also- if We do have thrush who do I call to be seen by? My midwife who delivered? My regular doctor? Help please!