How did you deal with the death of a friend you hadn't seen in a while?

My friend recently died of cancer at 24 (and a type of cancer which is extremely uncommon in someone of her age). We were very close in high school but didn’t talk much once we went to college. I had known she had some health issues going on but she was always really private about it and I had no idea how little time she had left.

The last time I talked to her was a bit over a year ago when she was diagnosed (though I didn’t know at the time). She was so smart and had so many ambitions, and I always thought we’d get back in touch.

I never imagined when we met that that was the last decade of her life. I feel guilty, with deep regrets. I’ve known people who have died, but never someone I was as close to.

I feel numb, and shocked, and angry, and devestated, and everything. I don’t know how to process this. Thanks for any help.