Tiktok - I wasn't meaing to imply that weight didn't matter at all - just not to worry overly about it if everything else seems fine.
My ds was happy, healthy and alert, with plenty wet and dirt nappies, not dehydrated but only gained weight extremely slowly. He WAS checked out, but the consultant wasn't at all concerned about this manifestly healthy baby in front of him - even if he wasn't following the growth curves. Even giving every second feed as EBM, and supplementing after feeds with EBM didn't change his rate of weight gain, even though I could SEE he was drinking loads - so I stopped bothering and went back to "proper" breast feeding (with only the occasional bottle of EBM)and stopped worrying about his slow weight gain - and started appreciating the fact that he was sleeping through! In fact, I stopped weighing him regularly at about 4 months old (which was when I went back to work and was difficult anyway).
The b/f counsellors at the support group (at the maternity hospital) said he a good example of a "NON-failure-to-thrive" baby who wasn't following the growth curves and would often get me to talk to some of the "newer" mothers who were getting obsessed with their babies' weight.
For the record, I went on to feed for over a year, and he is is now a healthy 3 year old who is (I think!) about average for both weight and height.
I suppose my point is "don't obsess about weight" - use your eyes and common sense. As long as you are confident that all the other elements are OK, make sure to enjoy the baby! In any event Bluebear's baby IS gaining weight, so she should just thank her lucky stars!