Empty nester

We raised our children to be strong and independent.  We told them they could be and do anything they worked and dreamed their way towards.  They are all impressive, strong women.  Women that I like and admire.
So how come, after all these years of love, worry, support, dreams, etc., it isn't easier to let go?
Youngest baby girl has started her life adventure as a full time college student, for her junior year, away from home.  She's less than two hours away, but, there's this hole inside of me, the empty mom spot, for lack of something better.
We've spoken on the phone (which means I can still make mom noises about eating, etc.).
When she tells me she's homesick, I have to hold tight to the weak mom inside of me who wants to throw open her arms and say "Come HOME".  Because, that isn't what she really needs.  She needs to know I'm still here, that I will always be here.  That home is not something that will ever end, as long as her dad and I exist, and then, it will still exist for her, in dreams and memories.  That the roots she has are strong, no matter where she goes.
She has the soul of an artist, my baby girl, along with scientific curiosity that is as charming as it is intense.  Her dad is a "why" person, as is she.  I'd like to think her love of books comes from me, although she reads literature in such a matter-of-fact way, it is impressive.  I am a reader who escapes into places I only wish existed, and yes, my favorite TV show will forever be Buffy the Vampire Slayer.
But, I digress.  Which isn't surprising, since I've been unfocused all week.  So, when your mom role changes, shouldn't there be a clear path through the empty nest?  With the other two, I cleaned their rooms, first.  Apparently, cleaning the first room and using it for other stuff, was not appreciated by my first little bird who left home.  I didn't actually use it for much of anything, until she rarely came home for visits.  Then, I confess, we used it for a guest who stayed with us for several months, and of course, storage.  So with the second, I cleaned her room, rearranged the furniture, and it became a really nice guest room (until she wanted the bed for her first two bedroom apartment, so that she had a guest room).  It then became my husband's computer room.. I did set up another guest room downstairs on a finished, enclosed porch, so that my mom had a place to sleep when she comes for a visit (she can't do stairs anymore).
This past weekend, after returning to an empty house littered with the debris of her leaving, I went up to her room, thinking I would clean it.  But, instead, I closed the door.  I couldn't deal with it.  So, I read a really good book, cleaned stuff, listed collectibles on Ebay that I had forgotten I even had, so that someone else could actually enjoy them (after going through a display cabinet and a closet).  I guess cleaning in some form is on my path, at least.
She's coming home for the Labor Day holiday weekend, so I've promised her her favorite casserole, a shopping trip for things she still needs.  I guess, I'll keep trying to figure this out.  Maybe I can even enjoy the fact that my third college student is on her way to the goal.  Because, I am proud of her.  I just miss her, and her place at home feels so empty.