As a mother I can see her concern.
You say you use drawing to vent.
For whatever reason you need to vent, deep down do you really want some help? Maybe she's waiting for you to ask.
Don't know your age but at any age counseling is a consideration.
If you're over 18 she doesn't have to know, like if you talk to someone free at your college.
Anyway don't know if this helps but take care of yourself.