weight gain with breast feeding

My baby is 4 weeks old tomorrow and has only gained ounces since Birth. Started at 8.4 and was weighed Monday at 8.6.. I'm worried age isn't gaining enough. Am I the only one? Is this normal or should I take her to see the pediatrician?

What sort of scale are you using, mama? A professional baby scale, accurate to the 1/10th of an oz, or a kitchen or bathroom scale?

Is the midwives scale. My husband studs is an old food weighing scale? Does it make any difference? I could try weighing her with my home scale

It's not normal for a baby to have gained so little in 4 weeks. But weight checks can sometimes be misleading particularly in the early weeks.

So both weights were done on the midwife's scale-and it's an old food weighing scale??? not a digital readout infant scale?
Were any other weight checks done between birth and now?
Were you planning on seeing a pediatrician anyway, or have you seen one?
What did your midwife say about the weight gain, your baby's overall health, and seeing a doctor?
how often does baby nurse (how many times in 24 hours) and about how long are nursing sessions? is nursing comfortable for you?
How has baby's output been-is baby pooping, how often, what does the poop look like?
How does your baby look/feel to you?

LLLMeg gave excellent advice and asked some great questions.

I just want to add that weight checks on unreliable scales or even just different scales can give very misleading information about growth. I know this from experience; my second baby was born at home and weighed 8 lbs, 6 oz on the midwife's spring scale. The next day I took her to the pediatrician's office and their scale said she weighed something like 7 lbs, 2 oz. So, either my baby lost over a pound in 24 hours or, much more likely, there was a big difference between the midwife's scale and the pediatrician's scale.