Low percentile baby

Anyone else have a baby that’s low on the percentiles for weight? My babe is 9 months and is 15 lb 8 oz which is the 4th percentile. She had been in the 20th percentile at her 6 month appt so she’s dropped quite a bit. The dr was concerned. I’m so stressed. My baby is beginning to not care about milk (she’s breastfed) because she’s just so distracted and active. She’s started crawling at 6 months and is now constantly standing up and walking along furniture. She never stops. I think part of the problem is that she burns so many calories and then along with not being a big eater.. ugh

She never liked purées. She likes food and I try to give her foods higher in fat like peanut butter and yogurt but she just isnt gaining like she should.

Dr suggested doing milk in a sippy (she gets pumped milk while I’m at work and that’s when she eats the least amount of milk) but we’ve already tried. Anyone else in the same boat?

She looks healthy not skinny. but just little. She’s 26.5 inches for reference. Which is the 20th percentile.