3 month old no appetite & weight loss

Hello! My almost 3 month old used to be a great eater, but then in the last couple weeks it has become a battle to breast feed her. She latches on and off and it’s a struggle to get her to eat more than 7 minutes. She will suck for a couple minutes and then unlatch and just stare up at me. I’ve tried burping her, switching positions, breasts, taking a break and retrying. She is a healthy chunkster weighing 15 pounds, but her loss of appetite has now made her lose some weight and I’m worried for her and for my supply. She still produces 3-4 poopy diapers per day. Any ideas what may be going on or is this normal because she is in a growth lull? She doesn’t seem to have an ear infection. Any tips on what I can try to get her to eat longer?

Thank you in advance!