ah hun I hate how the older generation think they know it all and feel it is thier place to comment on these sorts of things. I agree if she wasn't going to be supportive she shouldn't have said anything at all.
Concentrate on the good things, she did put on 240 g in 6 days which is a massive HUGE weight gain well done. Looking at your photo, not sure when it was taken but I can see beautiful chubby cheeks and she doesn't look boney at all.
You have come so far and things will continue to get better, you will still have trying periods but you have built up so much strength during this period.
You will find as she gets older she will get use to your supply, I know my DS use to 'choke' a little at first but it settled within a few months. The 2 hr feeds is fairly normal, she may not feed that often everyday but there will be days when she does.

You are such an inspiration, thankyou for continuing to share your journey with us.