Underweight and pumping made you worse ?

Good afternoon ladies :) I had a question and I want to read any type of experience you guys had while pumping considering weight, I unfortunately got a comment saying if I’m “eating right” because I “look skinny” and that “ pumping was a method used by mothers who want to lose weight” , I’m very tiny and skinny and I always felt so so insecure about myself (92 pounds) I went up during my pregnancy at 120 maybe and I was so happy but now that I’m pumping I do feel skinnier. Is that really a thing ? I know somebody here also mentioned your booty fat kind of goes away, eventually if I stop pumping will my weight come back ?