I'm sorry for your pain. It really, really stinks.
I did three things that helped me initially.
One- posted the serenity prayer on my bathroom mirror so I saw it brushing my teeth each morning and said it. Out loud.
Two- posted a gratitude list of ways my life was more peaceful and less chaotic. I recommend putting it right next to the prayer.
Three- I didn't do this, but it could help to post a list of the most painful things she did.
I was grateful for the ability to walk away from people drinking, from people acting in toxic ways, etc. The power to choose my space is something I gained.
I also joined some groups that interested me on a site called meetup. You can find groups in most cities with all types of interests you may have. I joined a bunch and met a lot of new people. You take or leave them...companionship at your fingertips, no strings attached. There was literally something almost every day I could have done. It helps get you out and chase away the lonelies.
Might not be for you...but a step out was a step forward for me.
Hugs!!!