Oh love! I know just what you mean!
I still look at women with buggies and I am incredulous that my time for that has gone - but, surely, it was such a short time ago?? I cant believe it's over. Did older women look at me when I had my brood and feel the same? I even have to bite my tongue and not say 'Treasure this time, it goes so quickly!' But it really, really does. Like a flash.
I'm a few years in from the kids going and I can say it gets easier - over time. I thought I'd bound into my new (free) life with joy... but it wasn't like that. It was a major and fundamental adjustment and it took time.
It looks like we both did the job more or less single handed - hence the screeching adjustment when the time comes. I can say, though, that I do enjoy a deep sense of peace these days. It took a while though.
I don't think you can hurry it tbh, it just does take time. Grieving, really - for a life that has gone. I enjoyed it immensely and it's hard to accept its gone. I remember my aunt (also a LP) telling me that when her youngest left home she climbed into his bed and sobbed. He would never know that, of course, but it was a comfort to me that someone knew how I felt.
I have found that being alone is one of the best kept secrets - but it took a while to find that out. I'd still, in a heartbeat, like just a moment of the hubbub of my babes at home welling up here but we did a good job, yes?