I do sympathise. You have already received some good advice, here are a few more ideas.
Try to get the baby to feed from different positions during a feed. It may be that one of the ducts isn’t emptying properly.
Lie baby on a mat, feed by going on all fours (knees and elbows), let gravity help to clear the possible blockage.
Tuck baby under your arm, with her feet under your arm pit and feed.
Again the change of position can help to clear any blockage.
When baby is feeding, gently stroke the breast towards the nipple.
Make sure you wear a nursing bra that isn’t too tight. Don’t wear tight restrictive clothing or a bra with an underwire.
Perseverance is the key. You are not doing anything wrong. I’m sure it will settle down soon.
Do keep trying a couple of different positions, and a different position again for the next feed each time, even after the infection is cleared. Prevention is better than the cure!
Good luck, you will get there in the end!