It IS a big change when the last one leaves the nest. Speaking as a single mother, and having only them in my home, I am very close to my girls (not that you have to be a single mother to be close to your kids.) When the first daughter left (both mine left when they married because they went to local CalState colleges and lived at home) I was comforted to know my younger daughter was still with me. When she married I KNEW I'd feel alone.
BUT, I didn't want to go around feeling sorry for myself nor did I want to be a mother hen with my adult girls. So, I tried to turn it into a positive that worked for me. I was focused more on my "independence" and looked at the advantages. My philosophy was and still is, "I can do whatever the hell I want to do, without answering to anyone." It is pretty cool but it's not like I lived on the edge, more of a state of mind type thing.
One of my first "brave" (for me) moves was taking a trip way to the other Coast all by myself. Yep, NYC!!! I look at my first trip there as a beginning of sorts.
TIS
"Mankind must put an end to war before war puts an end to mankind. War will exist until that distant day when the conscientious objector enjoys the same reputation and prestige that the warrior does today." JFK