My grandmother is my best friend, and she just passed away. Any way to process this better?

I feel like I'm dying inside. She was one of the only family members I have a good relationship with. We have been best friends and attached at the hip since I was a young girl. She always referred to me as "twin" because we looked so much alike. Losing her is like losing a huge chunk of my heart.. I've never lost anyone this close to me, and I can't stop crying to the point where my eyes are hurting and swollen. I know death and loss is a part of life, but I have no idea how to process or deal with this big of a loss. I'm desperate here..