Oh Emma, that is so sad about these "so-called" friends, it must be so hurtful. The only thing I can say if you choose to confront her be prepared for a possible additional hurt, or maybe she may surprise you in a positive way, but I don't know if she and the other person have said such terrible things.
If you feel you just have to get it off your chest then try it but remember the caveats.
If you feel you can let it slide and it won't eat away at you, then do so but be "cool" with them, they may ask you why you are being so distant and then that may be an opportunity to discuss it. Remember people that can do that to someone aren't worth your investment, and you do not deserve to be treated like that.
I wish you luck with this, and remember too, you can always stop here and talk, there is lots of nice, warm people that come here

Please take care now,
"darkeyes"

In giving advice seek to help, not please your friend
SOLON