1 week old eating habits?

My little girl has only today begun to eat 1 oz these past few feedings. A little while prior to this she had a good 3 oz feed. I know baby feedings fluctuate, but when should I be worried? I fear I am doing something wrong.

Edit: Minutes after making this post she let's me know she's hungry. Maybe I should just relax, keep an eye on her, and have her decide how much she feeds before I go insane, lol.