Early dementia

 My mother hasn't laughed in over two years. She hasn't smiled in over two years unless she's posing for a photograph, when she manages to fake it for 30 seconds. My mother has depression and anxiety and she is being kept medicated below normal so she doesn't keep peaking and troughing like a yoyo. The peaks and troughs were horrendous but now she just functions. She doesn't have any character. It's like she's been lobotomised somewhat. Able to talk and read and walk and do yoga but void of any personality. Any personality that I recognise as being my mother. I miss her so much. She is not the person that brought me up, full of excitement for life. She is an empty shell. My father is on antidepressants to deal with it. I don't know how he does it. Day after day with my non-mother. He must not recognise his wife in there. The amazing wife who wanted to travel and discover and live life to the full. He must be in so much despair a lot of the time because it's as if 80% of her is dead.
I get angry a lot of the time. Simple things she is incapable of doing. Simple things. I gave her my old iPhone and spent hours teaching her how to use it. Simple things like emailing. Yet she picks it up once a week and refuses to try. I really needed the money from selling it but she begged me to give it to her. She promised she would practise every day. Send emails. Every time I return home I find it covered in dust. She hasn't picked it up for weeks. She therefore forgets what I have shown her. And begs me again to show her. I have no will left. I get impatient then angry then I shout and then I cry. She makes me into a monster. I hate myself. I try to be calm and patient but she pushes and pushes until I explode. Then I cry and hate myself once more.
I hate who I become when I'm with her. I resent her for not wanting to be better. I shout at her because I'm so frustrated. I can't bear to be around her. But I miss her and love her and don't like this person my mother has become. I don't like the stranger. I don't like her. It's as if a hideous stepford alien being has put on my mother's skin. I don't like what's inside. This anxious frail uninterested dull person. Where has my mother gone? Where can I find her? I cannot bear to think of her not being in my life anymore.