I lost my dad/best friend last night.
I lost my dad to the same thing, an aneurysm in his head.
He was fighting Lymphoma and high blood pressure.
Within an hour after finding out the bad news, I felt this "alone" feeling come over me, realizing that he's now gone forever....
I know exactly what you mean when you say to spend time with your parents and let them know how you feel about them....
Condolences to you and your family.