You've already been working towards simplifying your life. That's a great goal, but you gotta keep going. We all get in a rut and lose hope. You're doing great!
Reevaluating your priorities might help. What is your energy best spent doing right now? What benefits can you reap from doing that activity? Can you afford to expend energy on a passion project? Is this a realistic future you're envisioning?
As I see it, your time belongs to you. There are things you have to do with it (work, help parents, sleep, etc) but the rest is yours. It's ok to carve out time for something that helps you grow as a person like illustrating and reading and such. You don't have to feel guilty for being "unproductive" in other people's eyes. This is something that took me a long time to learn. My dad was very hard on me and my sisters so taking time for myself to just chill makes me feel very guilty, even though it's necessary for everyone to do that from time to time.
Please remind your mother that comparison is the thief of joy. If she wanted to steal all of your life's joy away, she's found a way to do it. Such cruelty should not be displayed by a mother.
If you bumped shoulders with someone, you'd say sorry and move on. If you knew that someone had bad arthritis in their shoulders, you'd take extra special care to avoid bumping them right? You'd only know what effect your actions have on someone if they told you. You have to tell the people you live with what their actions do to you. Otherwise you'll be harboring these very negative feelings and they won't know why. If you don't voice what goes on for you, then you deserve to suffer the consequences. It is YOUR responsibility to make it known. If they don't care, so be it, but you need to take that step.