My mom's in hospice and I'm already grieving -- for her and my identity as a caregiver

Another suggestion to help with the grieving is to volunteer with the eldery in your community. Volunteer driving the eldery to medical appointments or volunteer at a nearby nursing home or assisted living building. If you are grieving the caretaking role, then continue it by helping those in your community who might not have family nearby. There is always a need for this.