I am very sorry you’re having this struggle. But it does sound like your mom may not be the right person to help. That is unfortunate, but you’ve already learned that she does the wrong thing when you’re vulnerable with her. The sadness and suicidal thoughts are important indications that you want to address now — and with someone who can help directly.
I would highly recommend talking to your school’s guidance counselor. At 14-years-old, school systems can help in those places where families can’t. The important thing is not to feel alone with this. I think your resilience and coping with your emotions and your family needs some outside support. The school’s guidance counselor is a great place to start.