Picked on at work

I have this new supervisor who keeps picking on me because I’m pregnant. I’m 8 months, I do what I’m told & never use pregnancy as an excuse BUT I do move a little slower, take my time & sit more frequently. So she says things like “pregnancy isn’t a injury” “why are u tired, u haven’t done anything” & “u put yourself in this situation” I finally had enough & said “I know it’s been 30 or 40 yrs since u gave birth but pregnancy is tiring” she’s not even that old I just felt like being a bitch lol she didn’t like that comment but oh well leave me tf alone. Everyone else is understanding & doesn’t bother me as long as I get done what I need but she has it out for me for whatever reason