Background: My DS is 6 months as of yesterday. He's a happy little dude - smiling, laughing, "talking" all the time, awake for 2 hrs at a time between naps, and active as can be (doesn't sit unassisted but is already up on all fours ready to crawl).
We dabbled with some solids at the instruction of the pediatrician starting at 5 months - basically we made it through all the stage 1 baby foods, but not on a consistent basis, maybe once every 2-3 days we'd give him some solids.
Other than the infrequent solids, he's exclusively breastfed. He generally eats every 2-3 hours, with a 4 hr stretch when he has his longer nap in the afternoon. Sometimes he wakes up between 3-4am to eat, but most nights he goes 12hrs straight (7pm-7am). I always let him nurse as long as he wants on both sides, and let him decide when he's done. Sometimes he finishes both sides and cries, but refuses to take the breast again, and then calms down within a minute and is happy for the next couple hours.
At his appointment yesterday, we discovered he hasn't gained any weight since 3 months. Dr called it FTT. He had a sick visit where he was up 4 oz from his 3 month visit, but he's back to the same weight he was at that 3 month visit now. He HAS doubled his birth weight, but that was at his 3 month visit (he's 6oz over). He also grew 2 inches from 4-6 months and his head gained an inch as well.
Dr instructed me to start giving him solids at least 2x a day (as much as he wants in a sitting) and try to get at least 4oz of formula in him daily to up his calorie intake. What could I be doing wrong that he needs so much extra, but seems so content?? When I've been away for a day and pumped, I got 30+oz and he only took about 28oz total.
I guess at this point if we're adding food it's not all that big of a deal to add 4oz of formula (instead of water, since he was supposed to be starting with 4-6oz of water at this age?), but I just kind of feel like there's got to be something wrong with my milk that he just isn't growing, even though it seems like he's getting enough??
Thoughts/advice/opinions/etc - please :-)