Being called sir

So, hey I just wanted to share something.
I'm a girl, with short hair and I'm often mistaken for a boy, called sir or whatever.
And I think it doesn't bother me that much when I'm alone, but when I'm with a friend or family member they usually are more embarassed that I am and correct the person right away, or they just look at me and laught, make fun of me. And thats when it bothers me the most.
So I dont know how to react or what to say.
Anyone in thug situation ?