Just adding a very late reply to this!
My full term weight was 78kgs (171 lbs), within 2 weeks of little one arriving I was 64kgs (141 lbs) and stuck exactly there for what felt like forever. My baby is 9 months old now and I have only recently started having some bursts of weight loss here and there. To me it just felt like my body is hanging onto that extra and won’t let it go. I think my bursts of weight loss happen when weaning is going well and baby is getting more calories from real food, but it seems to stall or even revert when she has odd days of wanting to nurse like crazy.
I’ve generally found that while breastfeeding exercise wipes me out way too much so I’m just sticking to walking (I think it is a combination of having higher energy needs overall, and not getting enough rest/sleep to recover because of the night time nursing). I’ve recently come to realise that I need to let go of thinking about weight loss until baby is weaned and I have my body back.