bad news baby

My husband and I have been together for 7 years and have 3 beautiful children, two boys (Ezra & Elias) and one daughter (Zara). I have a job where I make my own hours so I have thankfully been able to stay at home with my kiddos. I love being a mom amd everything that comes with it. Our kids are amazing and we always get told how well behaved and pleasant they are. He and I are having baby fever again. We feel like we want to add our final member. Our only issue (and this may seem like a small issue but really affects us) is when people, whether friends or family, make comments like "wow, again? Thats just crazy!" Or "when will you be done?" Or (best one yet) "after this one you should consider permanent birth control". I just don't understand why these comments just spew out of people. It is so unnecessary and although yes it is our decision and it's something we want, I feel like if it happens I wouldn't want to tell anyone! I don't want it to affect my pregnancy although I know I can choose to let it roll. There are some words that stick, ya know? Ugh. We already get looks from people all the time (we are interracial as well) and comments like "wow your hands are so full huh?" Or "you had em all close to get it out of the way right?" WHAT?? If i even joke about it people get weird. Why does this affect people so much? They will not be the ones raising them! So crazy that this is a reason we are holding back! Im just kinda emotionally stuck here. Any words of wisdom from outside the box?