What you are describing is perfectly normal for a breastfed bub. How long is bubs sleeping for after his feed at 9pm???
It has been shown that breastmilk in the evening between about 4-5pm and like midnight has a higher fat content and hence, bubs can go for longer without a feed. As a result of her cluster feeding a night, would make sense as to why she is putting on a great amount of weight. It takes (approxminatley) 6-8weeks for your milk supply to settle and to get into more of a routine.
My daughter is fully breastfed and was doing exactly what u describe and started sleeping through at 8 1/2 weeks. Cluster feeding in the afternoon certainly assists this.
If you are breastfeeding on demand, there isnt a 'routine' as such, although my daughter is 14weeks and she usually feeds at around the same times everyday. Ie. 7am (when she wakes up) 10am, 1pm, 3pm, 5pm, 7pm, and 9pm then goes to bed and sleeps through. My suggestion would be to try and get things done like dinner etc that are usually done between 4-9pm so you can focus on feeding bubs. It does get easier as u go along and bubs get extremely efficient at emptying the breastfed once it is establihsed with babies getting 85%of the feed in the first 5minutes. So me saying i feed ehr every 2hrs approx at night feeds are only 15-20mins IN TOTAL!
As for not having enough to give her, it takes approx. 20mins for milk to begin to fill up the breast again for bubs to feed. It is hard to gauge HOW MUCH milk bubs is getting but by the sounds of it she is doing fine and if you didnt have enough milk then bubs wouldnt be putting on weight. As bub is latched to the breast we have no idea how many mLs as bottle feeding.
Also, the problem at night about your breasts being really full, i had the same problem but at around 11weeks this also settled down and my daughter cluster feeds at night also and sleeps through till 7am. To start with my boobs would leak TONNES and would be painful to feed in the mornings like when the letdown happened. But this also has settled down and i have no longer got any problems. As for your breasts being sore, try to ensure bubs is attached properly in the big morning feed when ur boobs are super full.
Hope this helps, and if u feel comfortable and happy with breastfeeding, then i would encourage you to perservere as it does get better! Take care and all the best! Hope you make the right decision for you and your situation.
DD#1 - 3.7yrs, DD#2 -20mnths, DD#3 is here! 21.08.