Don't worry so much, the ears can sometimes take up to 7 months to stand up.
She is teething right now, so it's totally normal that her ears are up and down.
And you know what? Even if they don't fully stand so what? She's not a show
dog, she's your princess, perfect in every way. My Chanel has floppy ears, I
don't love her any less because of it, actually I think they give her extra character.