My mother had a relapse today. My heart is broken.

After 8 months sober, today she got drunk. I still cannot believe it, I am still in shock. She is an absulutely wonderful person when sober, and an absolute devil when drunk. Today I had a nervous breakdown, tomorrow it will be just pure sadness. No one understands why her returning to alcohol gets me every time, but it does, and I dont know how to deal with it. She is the only person in the world that is always here for me. And now I dont want her to be. I am sick and have had a terrible last year, through which she helped me by being sober. Now it is all over and everything is fucked.