Congratulations on your baby! It sounds like you're both doing very well

As for the time thing - it's all normal. They change, constantly, and will continue to do so well past weaning age. No baby - regardless of what any book or person may say - is 100% set in a 'schedule'. They are growing and developing so rapidly it would be totally unrealistic to expect otherwise.
Breastfeeding is a really robust system and most of the time it works if you just follow your baby's lead. He asks for milk, you provide it

Enjoy your sleep and give yourself a pat on the back for your good work so far