I think most parents worry about this, especially with the first baby. My daughter was a big gainer early on, nearly a pound a week some weeks..

.. but she dropped right back, thinned out and lost that chubby baby look. She was quite lean by the time she was 7-8 months, but very healthy! It simply isn't normal for babies to gain the same amount of weight each week - think how big they would be by the time they started school.

You may also notice over the next few weeks that your breasts stop feeling full (if they haven't already). This doesn't mean you're low on milk, it's completely normal and just means that your breasts have regulated the supply to your baby's demand - trust me, things get more comfortable after this.
Watch your baby, not the scales. Overall, is she happy and alert? Healthy looking? Wet nappies? Generally babies find a growth curve over a period of time and more or less stick to it. It's normal after only a few weigh ins that she could move into different percentiles.