Hi S,
I am so sorry for your loss and, unfortunately for me, I'm familiar with what you're going through right now. My mom passed away June 16th 2005 when I was 17, only a bit over a week after I graduated high school. I know what you mean when you say you can't bear the fact that your mom won't be with you for major events in your life. My first year in college was a living hell because of my grief. I don't even know why I went straight into college after the tragedies I experienced that year. But that's another story. The only way I've found to deal with the fact that my mom won't be physically present with me during important times of my life is the knowledge that she lives on in my heart, hopes, and ambitions. She and I were all the family we really had (not literally, but figuratively speaking), and I know that since I'm doing the best I can with my life right now, she would be proud of me. I hope you can find a similar feeling; your mother will live on in your memories and your heart.
I also understand what it's like to be unable to discuss grief in real life with friends or family. I always choked up whenever I talked about her, and often still do.
Knowing the pain that your mother experienced during her last days is also very tough. My mother died of a heart attack: she couldn't breathe and was kicking and screaming for air. I can't imagine, nor do I want to imagine, the misery she was in during her last moments on earth. The one consolation is that our mothers will never have to feel that pain again.
I'm starting to get choked up right now, so I'm going to end this entry. My thoughts are with you. Take care of yourself.
J