Can you please, help me with this?

Ok, my best friend lost her mother 5 years ago. They were very close and it was a huge loss for her. I tried to help her a lot. She liked it at first until last year that I appeared uninvited for her mother's death anniversary. I just went to her city and emailed her that I was there if she needed me. She didn't like it at all. I apologized. I thought it'd be nice. I would like someone do that for me. Now, for this year's anniversary that they celebrate, she just took a vacation and went away. Is she that mad at me because of it? I don't want to complain but last year she warmly thanked everybody who remembered her mother except me! I had done the most. I kept emailing her because we live far away, I wrote all calming words and everything. Anyway, this year, should I send an email just a few sentences of sympathy? And then what? Why is she aviding me like plague at this time but generally, she tells me to keep in touch with her and gets worried if I don't email her. How do you deal with such a difficult person?