I think it's since the most recent molar came in, she just sort of sucks the nipple and can't be getting much milk. She's happy to accept an extremely short BF eg tonight she had less than 20 seconds per side but it is so painful.
I've explained that it hurts me and tried a cup instead but she still wants a BF. I need her to adjust to these new teeth pronto, or give up.
She is way more strong willed than me so anything involving a battle will be just that and I'm likely to lose!