Low self esteem.. Too big

I'm 18 weeks 1 day with my 3rd .. I have developed a pretty low self esteem due to how big I'm getting with this baby far bigger far faster then my previous 2 . ultimately I could handle this and I try not to get discouraged with my appearance however it's hard . there is this women at the school when I drop my son off who is always saying are you sure its not twins your a bit to big for only 1 baby and 4 months along . or wow I feel sorry for you its going to be a big baby look at how big you are , you know back in the day no matter how many kids we had we never got that big so soon . you look like your 8 months wow . it's just frustrating and hurtful as I already feel to large and have my own insecurities I don't need to hear comments like this from an old witch . I suppose it doesn't help much when my husband says I'm huge too and makes comments about me being fat then laughs it off being like your pregnant relax. I've always been a small girl up until I got married then for some reason I gained 20 lbs out of no where then got pregnant . it's emotionally exhausting trying not to let these comments bug me . anyways long story short do you all really think I'm tooo big for 18 weeks with my 3rd ? And would you all say I look more "fat" then pregnant ? I'm not seeking attention just the truth and a little support to stay positive :)