While I always say that you should trust your own intuition first, my experience would tell me that you dont need to worry yet. The problem is that at 6 weeks, and then again at about 3 months, babies hit some pretty big growth spurts, and eat a ton. She got sick right at that change over, so you did not see a gradual change, but at 4 months all 4 of my children slowed down. But by 6 months, they were eating tons. Your schedule sounds great, every 4 hours, whatever she wants to eat as long as she is happy, growing, reaching her milestones, and sleeping well, you should not have need to worry. It is great that even while she was sick she gained some weight. Watch her growth pattern, like if she has always been in the 95% for her weight, but now is in the 50th, I would question. As soon as she starts moving around more, like crawling etc, she will burn more calories and need more food. I hope that helps some. If you have any other questions, feel free to ask. Like I always say, I dont claim to be an expert, but 16 years in childcare, and 4 kids of my own has at least taught me a few things:) ~A.~