When you go through something like this you do a lot of reflecting. You begin to think of how trivial some things are and the importance of others.
Truer words were never spoken. I know exactly how you feel, as I lost my sister almost a year ago--it made me live differently since that day. You have no idea how much it breaks my heart to even type the word "sister," and I'm tearing up with sadness for you, empathizing so deeply with you now with this news you deliver. I am just so, so sorry for you and your family now.