(((Hugs))) It was REALLY hard for me too. I cried each time one of them left for college, and then within a short time two years ago - they all three got married and my baby daughter left for Japan. It was all pretty sudden too (short engagements for two of them) and my daughter (only daughter, too) married and left the country less than a month later.
Like I said - it was hard and we were also going through some *terrible* stress (financial, legal, personal)
I know many folks can see it in a positive way - but most do go through a period of sadness and adjustment.
I hope the sadness is short for you and you can maybe find some new things to keep your interest and help you get through it.
More (((HUGS)))))