I cried because my house was empty

My son is moved out if the house with his boyfriend Ethan. They were over here not too long ago to celebrate is 19th birthday and then over again for dinner. I knew this day was coming but... What do I do now that I have an empty house..I keep my son's room the same in case for some reason they need to.move back in. I guess I'm so emotional about this. I used to woke up on Saturday to my son watching tv(or him and Ethan watching tv) and now that spot on the couch.is empty... I never knew watching my son leave the nest would be so hard.