Hi, I could feel your hurt right through the computer screen....
First, I would either print off this page or e-mail it to your mom... (see "Thread Tools" on the blue bar above the posts). You expressed yourself very well, and without knowing what was happening with you for that year that you mention it is hard to help you find a way to talk to her about it.
Can you share some of that with us?
Also, think of some concrete things you can do, help out with, or just send a hello card in the mail every couple weeks.
The other possibility is that she has had some problems of her own in the last year that have affected her - how old is she?
Once again, not knowing the situation Alzheimer's was my first thought when you described her behavior...
Hoping you can help fill in some of the blanks that led you to this point,