weight gain curve drop

Baby is now 6w old. She was born on the 50% curve of height and weight and kept at it 'till 04 weeks. Now dropped to 25% continuing EBF. Milk supply is good, sleep pattern not so much since she does only about 2 max 3 periods of 3 hours sleep. Also the most of her BF sessions lasts between 05-10 minutes long. She breastfeeds many times during the day - at least for one whole period every day she'll nurse every hour and a half. Any ideas?