The loneliness of having a teenager. Of course this is not to be compared to anything more serious, such as losing a child. This is a specific type of loneliness that all parents will experience.
It’s like you had a puppy and then a great dog for the past twelve years, then one day it starts acting like a cat. He still loves you, but he is no longer affection, cuddly, or happy to see you. His eyes don’t light up, he doesn’t greet you at the door or bounce on your lap. You are still expected to meet his needs, but affection is on his terms. If you try to force affection, you get badly scratched. So you accept your cat, and his cat terms, and patiently await the day the dog comes back. (I’ve heard it is so.)
Yes, this is “normal”, yes, everyone goes through it. But it still feels awful lonely when your kid doesn’t want to talk like they used to. Or they’d rather be with their friends. You are proud of him for becoming independent, but you miss your pup.
I will call this “matersolum”. (Mother – lonely) or patersolum for the dads.