Yes, I've got used to only having the one DC at home now. It definitely makes for less bumpy family dynamics. I was frazzled a couple of weeks ago when they were both here, being super noisy and reverting to that siblings vs parents thing! DS acting like he's about 14 and DD just being much harder work than she is when on her own.
Glad you had enjoyable times at the graduation ceremony, meal and other celebrations at Durham @Benjispruce4 @jano69 and @bigTillyMint . You will be exhausted and hoping you've recovered from any lingering sleep deprivation and too much to drink.
It certainly is the end of an era 