I'll definitely try this Deb, thanks!!
So I went to see the LC this morning, she's not concerned about the weight gain but she is concerned about her low milk intake and that her diapers are not wet enough (when I went she had the same diaper on for about 3 hours and it was barely wet). I fed her there and she really didn't drink much, when my letdown happens, she drinks for 2-3 minutes max and then stops she doesn't want it anymore, and same thing happens with the other breast. The LC thinks she's definitely not getting enough milk but she's not sure why. She told me to add another feeding during the day (feed her 5 times instead of 4, which I had already started a few days ago) and try to express some milk after she's done and give it to her in a cup. She said maybe DD doesn't like the milk flowing out fast but that doesn't make sense to me since she does drink for 2-3 minutes when let down occurs.
Anyhow just wanted to keep you all updated, thank for all the good advice and I'll continue to monitor the situations (I'm also seeing the LC again next week to follow up on this).