Awkward moment at breakfast

So this morning my husband and I decide to go out to breakfast since its been so long. We go have fun and ate some delicious food our waitress was super sweet she dropped off the check and kinda steps back over to us. She goes I just have to ask how much longer do you have left. I smile and pregnancy brain kicked it took me a min but I told I have a month left til my son is born. She congratulated us then proceeds to say I was gonna ask you earlier but I just thought maybe you were chubby and I didn't want to offend you then I noticed you rubbing and holding your belly. I had no idea what to say I smiled and laughed got up and paid our bill. Who does that to a stranger really.