Dealing with Grief and Depression on the Anniversary of My Mom's Death

today is the 15th anniversary of my mom's death. my mom was my whole world. I was only 14 when it happened, it was both expected and unexpected all at the same time. she was diagnosed with stage 4 Ovarian Cancer when I was 4 years old. they told her she only had a year to live but she somehow made it to almost 11. sitting and waiting for all that time wondering if today would be our last day. when it finally came. I fell back asleep like nothing had happened. I told my uncle "that's good" after he gave me the news. I hate this day. I hate the way it makes me feel. I hate that so many people don't understand. I hate that I never got to say goodbye. how do you handle your grief and how do you handle the depression it can cause?