Hi, well I'd say that it was really good that your friend is your ex-friend!! You really shouldn't be made to feel/or feel bad about letting out how you feel.
And perhaps see it as a good thing that she's replaced you, you're way better off without her by the sounds of it. So no more asking her questions hey?!!
Just give it a little time and allow yourself to make friends who are really going to care about you.
Now you're not "wallowing in self-pity" you're hurting, yes?!! So, we care, do you want to talk a bit more about it, we're here for you if/whenever you do.
Alison