My 18mo randomly self-weaned?

So I only breastfed during naps/bedtime. Starting yesterday, my son would start to breastfeed then would unlatch and fuss. I mean, I’m not complaining because I was more than ready to wean, however I just thought it was totally random and out of the blue. Is this usually how they self-wean? They just stop doing it completely? So you think something could be wrong? He is acting totally like himself.

Thanks!