Alone and lost

I'm in such a dark place right now. I trusted my best friend. I thought she was there for me in every way possible when it came to my family and my life. In a matter of months she destroyed my friendship I had built with my ex husband (for the sake of our children), my friends who I have struggled to make because of my anxiety and depression, my relationship with my family and to top it off my relationship with an amazing man who I love like I never thought I could.
My children are my whole world but I have no one now that wants me in their lives as a friend or as anything else for that matter. All because the person I thought I could trust used my past to creat doubts in my mind and made me believe the lies she was telling. She was my best friend and I believed her because I believed she was looking out for me.
The pain and hurt for losing the man I love is making me so sick. I never knew I could feel like this. I never knew love hurt so much. When I separated from my ex husband I was excited because I wanted to move on with my life and not have someone dictating what I could or could not do. I don't feel that way now. I feel lost, sad, angry, empty and a whole list of other words that won't ever fully describe exactly what I am feeling.
I don't know exactly what I am asking and I no longer know exactly what I am doing. I just don't know how to handle any of this anymore.