I don’t understand why you’d call her mom and then blow up at her for ignoring you when you knew she was out with a friend. I would also find that overbearing and kind of controlling. I can see why she wants a break. I don’t think she’s doing this in the best way, but it seems like she clearly wanted a little distance even before that based on her actions.
Please don’t call people’s mental health “absolutely whack.” That’s really not a kind way of phrasing it at all. When you’re facing depression or something else, you can’t just schedule a doctor visit and get out of it sometimes. That’s not how it works.
You can’t help her if she doesn’t want your help. Sometimes people don’t want help, they need space. You can’t fix her and if you’re looking at her like a problem to be fixed, I can see why she’d want even more space. Maybe in some days or weeks, she’ll come back to you, since she didn’t break up, but even if she doesn’t, maybe your jump to fix or help should be restrained a little. Ask if people want advice, help or an ear for them to vent. And listen to what they say they want, not what you think they need.