Insulted at 30 weeks

So today I was going through the gate of the base and was pulled over to have my car inspected. (its a security thing). I got out and opened my trunk and hood. As I stood there waiting to be done, a very large security police woman asked me how much longer I had. I told her 2 months. She said "Oh it must be a big baby!" I slammed my hood down and said "I am usually a size 2 and don't think I am that big." There was another male gate guard standing there and said " I don't think you are big at all." And then he told me his wife was pregnant and due on the 25th. I congratulated him and said thank you. Look at fatty, took my things and got in the car. And of course, I can think of a million things to say back to her now but in the moment, I am so flabbergasted I can't think straight. I just want to get away from people like her.