You seem to be seeing yourself through a distorted lens.
Your breasts are large, larger than they were in the past, I imagine, because you've recently had a baby, but they certainly don't look the way you've described them.
Your husband's best friend is being incredibly rude and judgemental if he's commenting on anyone's weight.
What gives him the right to give his opinion on how someone looks? Of course he's speaking from an aesthetic perspective, and it's his perspective of how he thinks people should look and what is a 'perfect' body, in his opinion.
You are clearly surrounded by people who are very into appearance and keeping fit and you are comparing yourself to them when you've recently had a baby.
Obviously, your husband's friend, this clearly, 'perfect' specimen of manhood hasn't recently had a baby and is therefore in perfect condition, bodywise. Shame his manners and attitude aren't just as perfect.
Stop telling yourself you're disgusting, you aren't and it's a horrible thing to say about anyone, so why say it about yourself.
I imagine, from the way you write about yourself that you were very slim before you got pregnant, well you're far from fat now, and you've just had a baby, for God's sake.
Go out tomorrow and try to feel confident in yourself. Stop comparing your body with people who haven't recently given birth, or anyone else come to that, and have a lovely time.