"Oh, no you don't!" she swore, giving him a light kick to the shin. "You don't get to tell me what I get to feel, Doctor! You're my best bleeding friend, and I don't know what I did to get you to want to avoid me, but I don't think I've done it yet, and maybe if you tell me what I did, I can avoid it this time!"

She knows they could fix whatever was set wrong. She was there when all of reality was rewritten by Morbius. She was there when the Doctor almost died to set it all right.

And the memory of almost losing the Doctor sets her emotions to jag again, realizing that she must have lost him again in the future, and she holds back another sob.

Which she covers with another (mostly gentle, really) kick to the shin. "Doctor, tell me what I did wrong! I want to be your friend again!"