Re: Worried about latch / weight gain
Welcome and congratulations both on the new baby and to making it to 7 weeks of nursing!
Based on the weights you posted, I don't see anything particularly worrisome in your baby's pattern of weight gain. It's pretty normal for babies to sort of wriggle around on the charts, and there's no reason to think that your baby should follow any given line on the chart for the entirety of her first year of growth. Often a baby will be follow one growth trajectory inside the womb and a different one outside the womb. Sometimes this means a baby is born small and then balloons, or is born large and then leans out. As long as there is growth occurring, and the baby is meeting milestones appropriately, there's rarely anything to worry about.
With regards to the latch, it doesn't really matter what the latch looks like. What matters is what it feels like and the baby's diaper output (see http://www.kellymom.com/bf/supply/enoughmilk-older.html for what to look for in baby who is >6 weeks).
Just one quick question- are you nursing on demand, or trying to stretch feedings out to meet a schedule?
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"