Too much weight gain

Hi all, I am in week29 now and so far I have already put on 11kg! My gynae has asked me to cut down on snacks etc but some mums also tell me, they had similar weight gains at this period so it’s not alarming. But I still find it a lot. To add a bit of background, I have hyperemesis gravidarum (since week6, and the whole 1st tri I was vomiting 8-15 times a day, and at my peak it was 30+++ a day. Week 18 onwards it declined a little to 10 times a day, and now at week 29 I’m down to 5 times a day. My pre-preg weight was 48kg (I’m 165cm) and I’ve always had trouble gaining weight, never once been in the acceptable weight range, even though my whole diet consists of carbs, fatty food and no greens. I’m worried and puzzled why I’m gaining so much weight despite having underweight problems my whole life and now vomiting several times a day.. Every night I go to bed with gastric cos I don’t dare to eat too much, but every time I step on the scales the number just increases. Anyone with HG also gaining weight like crazy???