Eating but not gaining?

[Minkness]

Hey guys. My little MBK is a fantastic eater but hasn't been growing too much. I have been feeding her 2 pinkies a week of varying sizes since I got her. She was 22 grams when I got her, then she went up to 26 grams, but is now 24 grams and has been 24 grams for 3 weeks now. I always weigh before a feeding, not after, and feed on a strict 7 day schedule to make sure I don't over or under feed her. I know that it's winter and I checked her temps, everything is perfect in her enclosure. I tried upping her to a fuzzy and she tried really hard, but couldn't seem to manage it, and won't take a 3rd pinky.

Am I doing something wrong, or is this one of those things that just requires patients?