Re: what does thrush look like?
I should have gone into a little more detail. So the pain you get right at the beginning of a feeding- that's something people call the "sizzle". The sizzle generally lasts for the first 10-60 seconds, and it's the feeling of the nipple starting out too shallow in the baby's mouth, and being compressed and hurt until the baby's sucking finally draws it back into the ideal position on the back of her tongue. The sizzle can re-occur during the feeding if the baby relaxes her latch, allowing the nipple to slip back onto the front of her tongue.
That being said, the following symptoms are suggestive of thrush: nipples which appear more pink and dry than usual, dry skin in the nipple area, and cracks. If you've had a recent course of antibiotics (including for GBS+ at the time of birth) or a recent yeast infection, that would elevate the possibility that this is thrush.
When the baby finishes nursing, do you see blanching at the tip of the nipple? In your first post you mention your nipples being lighter colored in the middle and then gradually darkening- that's a very good description of a vasospasm. The nipple starts out very pale in the center or at the tip, and gradually darkens and returns to a normal color.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"