Hammi, I would seriously question your TCM's expertise on breastfeeding. Research has shown that even nutritionally compromised mothers make excellent quality milk for their babies - it's highly unlikely there's anything wrong with yours.
I wouldn't worry about her weight per se, but look at all the other signs of health too. How many wet & dirty nappies? That's the best indication of how much milk she's getting, for instance. An increase in mobility will certainly make a difference also. And maybe the scales were wrong!Well yeah, in that case I'd just keep an eye on things, especially if she seems otherwise healthy.