Yay for the longer sleeps!!
Firstly, you have absolutely nothing to worry about - trust that you body is adjusting itself to produce enough milk for baby.. AFAIK, milk supply generally settles anywhere between 6-12 weeks, sometimes later. Thankfully too, cause that engorged feeling isn't too nice at times
Secondly, and more importantly, trust that wee Kiara will let you know if you aren't producing enough milk. As long as you are getting sufficient wet/dirty nappies (which is different for every baby - DD isn't a very heavy wetter at all) and she seems happy and content then you will be producing enough and she will be getting enough, I doubt that she would be pulling 6-8hr sleeps if she wasn't
Just for interests sake, DD was always a great sleeper as a wee one - 12 hours by 12 weeks (uncommon) but there were several periods where she woke consistently for anywhere between 2 weeks to a month to feed 3-5 times overnight. I found my supply adjusted to this very quickly, ie 1-3 days to accommodate her. Conversely, when she started sleeping through again it took the same amount of time for my supply to adjust back to not needing as much IYGWIM.
Unfortunetly, her latest waking period has lasted 3.5mths and counting
*sigh*
Anyway, apologies for the long-winded reply! Sounds completely normal, you're doing an awesome job!!