E's 6 month appt

It's still beyond me how she can be 6 months old already, but alas...she is growing up way too fast...well, in my eyes anyway. She's still 'petite' according to the nurse. She weighed only 13lbs 3.5oz and has dropped to the 10th percentile. Her length was 25.75in, which is in the 50% percentile. Because she dropped from the 25th percentile to the 10th percentile in weight, her pediatrician wants us to start supplementing her with formula at least a couple times a week. He also gave her a prescription for a Vitamin D and flouride supplement. We've been mixing 1/2 formula and 1/2 breast milk and she's been taking it fine. She also enjoys the baby food and is doing really well with a spoon. So far, she's had sweet potatoes, bananas and applesauce. I've even given her some rice rusks and she likes chewing on them. She goes back in 6wks for another weight check. Hopefully, she starts catching up! S was 16lbs 2oz when he was 6 months old.