Baby is a bit on the skinny side

I took Tristan to the doctor's today to get him measured and weighed. The last measurements taken were when he was 6 months old. We were a bit concerned since some people have mentioned that he was skinny (by some, I mean my parents) and his 6-12 months clothes are kind of swimming on him. In fact, he is still wearing a few outfits which are 6 months. Tristan will be 10 months old in 9 days.

Tristan measures 71 cm in length, which puts him in the 25-50% tile. That's where he was from the start so that's great. His weight, however, has now dropped him off from the 25-50% tile to the 10% tile. The doctor didn't seem that concerned when I told her what I was feeding him. I did mention that I am concerned that he might not be getting enough milk since I am no longer producing much. I only feed 3 times a day and on his daycare days, I pump only 3 oz. at lunch time. I'm sure he can drink more from me since he is a more efficient pump but still. At this stage, he should be getting around 24 oz. of milk a day. So the doctor is suggesting that maybe I can try to introduce some whole milk or formula milk on top of the breastmilk. So, I'm debating what to do right now. I would like to wait until he is 12 months before giving him whole milk but I'm already giving him cheese and yogurt.

The doctor said that it is normal that the baby doesn't gain much weight now that he is mobile. Tristan is crawling, standing, and always on the move. In fact, after lunch today, he crawled 4 flights of stairs - that's 28 steps! That must be a big workout for a baby. I grabbed him by the chest at one point and felt his heart pounding really fast. Good thing he always had a strong heart!

I think I would still like to hold off on the whole milk idea and give him formula instead. We do have some formula which we need to use up. I'll wait until he turns 10 months first. Until then, I'll up his dairy consumption of yogurt and cheese. It's only 9 days; I can live with that. In a month, we will go back to see the doctor and weigh him again. All in all, I'm not too worried. He doesn't look particularly skinny.