Oh, man....I'm so sorry. From her photo, she was a real beauty and I know a wonderful companion. I send my love and condolences to you.
Remember all of the good times together and that will help you get past this bad time....
I have a male cat that turned 10 last September, and I don't know what I
would do it he got sick and had to be put to sleep. I've done it only once
before, a Russian Blue female that ate some straw flowers, got some caught in her throat which caused a fatal tumor. I hated having to do it but I couldn't let her suffer any longer.
It was 6 years before I could even look at another cat or even think of getting another one...which is the one I have now.
Remember the good times and the love she gve you.....it may help, it did for me.