I'm not banded yet, so clearly not an expert, but I get the sense, from reading other's experiences that weight loss tends to slow when you get on solid food - and have not had a fill yet. It makes sense to me, at that point you've eaten so little for quite a while with pre-op and then liquid diet, so my guess is that your metabolism slows a little - plus you're hungry and relieved to eat solid food for the first time in weeks - and so a stall in weight loss is probably highly common for that period.
I assume you have just a few weeks until your first fill. Do your very best until then, and then hopefully it will get easier to keep your portions down.
:lb4: