Hi, Rachael -
I'm so sorry that you have received such hard news about your mother. You may never find answers to the questions of how and why her cancer came back so aggressively and quickly, and that can be as hard to take as the diagnosis. Please take care of yourself, as you and your family will be facing some rough times.
This is the right place to be for support and ideas on how to cope with treatment. In the meantime, you are in my thoughts and prayers.
Marlene