I also thought best friend was in love with you because he became distant after you started a relationship. I had many of those type "best friends" who were just acting for YEARS,but in fact wanted something more then friendship...
You have your boyfriend,at least someone valuable in your life and stick to it and cherish it. Same is my situation: except him i have no one else.
Just live your life,do what you are doing and I believe new people will come into your life. And about those two you should forget,they are just not worth it-karma will catch them eventually.
And I am sorry for your grandma(i loved mine as well very very much),they will live forever in our hearts and memories