Do you think kids know if you're pregnant?

So at my son's birthday party a few weeks ago my husband's brother (he's 7) asked me if we were having another baby. I said we would like to! And he goes "you probably are now" and walked away. I can't stop thinking about it!! It was so odd. Like he just came up to me randomly and asked/said that. I hope I'm pregnant! I feel like there have been several "symptoms" this month, lol but when are there not!? haha. Isn't that so strange though? People always say kids know the gender of the baby before it's born,, maybe he knows I'm preggo!! Hello two week wait, you're the bane of my existence.