Feeling obsolete

I have been blessed with a wonderful husband and two amazing kids.  My youngest left for college 2 weeks ago and I have been a mess ever since.  I didn't see this coming.  I thought I would enjoy the me time that would be available to me, but that is not the case. My daughter was diagnosed with generalized anxiety disorder when she was in preschool and has always relied on me to be a comfort and support to her.  I can't tell you how many nights I layed with her while she had a panic attack or cried herself to sleep.  Even before she left at 19 years old she slept in bed with me and told me I was her favorite human and she was scared she would miss me too much and want to come home.  I reassured her that I was always a facetime away and this was going to be good for her.  I was right, she is loving it there! I'm so proud of her and happy she is doing so well but I suddenly feel obsolete.  I feel thrown away, used up and tossed out.  I know that sounds terrible.  I just didnt think things would change so drastically for us.  She has pulled away from me and I fear I am no longer needed...by anyone.  The lonliness is deep and gutting.  My husband works and travels a lot for business.  My friends and sister all seem so busy with no time for my sad sack.  My parents passed away years ago and I dont have any family in the area.  I'm trying so hard to involve myself in other things like babysitting my nephew and joining classes etc.  But the lonliness and sadness are just so intense.  I just hate it all right now.  I'm lost