As someone who lives for being right all of the time and always seems to be trying to prove herself, the idea of giving up is almost the scariest thing that happens to me. It always seems to surprise me when I realize I cannot do everything by myself and can begin to see the reason behind needing to take a break from something, or just straight up quit. I am consistently scared of disappointing the people in my life or showing those who said I couldn't that they were right. This is a common fear (at least I hope it is) that almost everyone has experienced at some point in time.
Deciding to put your own mental health ahead of anything else is absolutely okay and is something that you should never be ashamed to admit. You do not owe an explanation to anybody in your life, and yes, that includes your mother, no matter how much she likes to pretend that this does not apply to her. There will never be anything more important to you than making sure that you are happy.
You will not be disappointing anyone by making time for yourself and making sure that you are stable. If there is anyone in your life that is upset by that, they should not be in your life. If they cannot appreciate you doing what is best for you and your life, they do not deserve to see you grow and blossom.
However, it is important to make the distinction between quitting something because it is what is best for you and laziness. There is a difference between taking care of yourself and just deciding to quit something because you do not feel like following through with a commitment.
But, it ultimately comes down to one thing: Self care should never be a disappointment.