With sadness and anger?
I'm trying to think of how I manage mine.
Thinking more positive, not dwelling on negative thoughts, face your fears...
Life is not over keep on living it to the fullest

Find out what triggers. This may be weird but when someone mentions Alzheimer's I will think of my dad and he passed away 4 years ago from it. He didn't treat his diabetes serious and it messed with his mind where he ended up with dementia.
But I will keep myself from thinking too much of it and thinking about something else or distract myself.

Everything is easier said than done in the beginning

What would you advise a 21 year regarding health and life in general would you give?