I'm going to yell at my mum for not caring about my future
How did you know she's not caring about your future?
She once said to me that "I had no purpose and she can't give a flying crap about it"
It's natural to expect support from your parents. Before yelling at her, why not initiate a respectful conversation about how her words made you feel?
She doesn't care so there is no point in talking about it.
I feel like she did not mean what she said and I obviously do not know the entire story, but what I can recommend is to try and get help from other family members like your father or your grandparents to see how they can help you with your relationship with your mother. I do hope you communicate with your mom calmly and respectfully, as she maybe dealing with a lot right now.