I lost my mom last January, she had ovarian cancer. While mine wasn't so unexpected as yours, I am sorry for your loss. I missed my mom on mother's day just as much as I did the last year, too. The ache and longing of wanting your mom there never gets any easier, but the pain does lessen over time. My first mother's day was extremely hard, I was actually in a lot of denial at that time and pushed a lot of my pain away, so dealing with it became a lot harder as the year went on.

I think for me, in the order I went through my grief was, denial (major) > anger > sad > and I'm just now being able to get through acceptance. Talking and sharing how I feel has helped a lot in my healing process. Hugs, if you ever need to talk I will listen.