mother in law

Mada
I'm having some trouble with my mother in law, but I don't know if the problem is mine and if I'm being over sensitive about it... 
With Christmas and all I've gained a little bit more weight than I was expecting, and I'm feeling really bad about it... I didn't plan the pregnancy and, although I'm really ansious to have my baby in my arms, I can't help but feeling sad and insecure about some changes in my body. 
I go to the gym everyday and I'm trying to be as healthy as possible, but I've gain 10kg in 24 weeks +1 day. 
My mother in law asked me how much weight did I gain in a dinner full of people, and my stupid boyfriend in his innocence told her, and she maked a disgusting face to me saying that she only gained 13 kg through all the pregnancy. I got so offended by the question, the face and the judgement that I just got up and leave. 
I didn't saw her since then, but I would like to ask you if is it me or is it a very rude question to ask in front of 20 people that i don't even know?? I'm I so wrong to be offended by it? I'm I the only one that is still adjusting to all the changes? I'm I being over sensitive? I'm I gaining too much weight??? 
😔😔 so lost with all these feelings.....