I don't mean to sound cheeky but I would say that 3-4 hours between feeds is not 'up all night' by a lot of people's standards on this board for a 2 week old baby. I'm sorry if that belittles how you are feeling. I hope it's reassuring on some warped level. If you've been having better nights than that until now then that's great.
Many newborns continue a feeding cycle of even less than 3 hours for 24 hours!! I'm not kidding. It was at least a month before I had more than a 3 hour interval between a feed at night and I know that I am not unusual.
A 2.5 hr pattern is also very very common on a normal day. A lot of people start EASY at 2.5-3 hours even after a few more weeks. If she's falling asleep you can try gentle stimulation but in truth she is fighting a powerful hormone in your milk that is sending her to sleep and it's hard. You will find before very long she stays awake more and her feeds start to stretch. Frequent feeding in the first few weeks really helps you to build up your milk supply and your levels of a hormone called prolactin. After the first few weeks the manufacture of that hormone changes so this time now helps establish your supply for the rest of your time breastfeeding.
It could also be that she is having a growth spurt right now - there's a huge one at 2 weeks. She really needs to feed regularly to build up your milk supply and sleeping will change too. As long as she has been waking to feed that is the important thing. 2 week old babies can't be kept awake if they are determined so I would rest yourself and see how the next few days play out. Growth spurts can last anything from 2-5 days.
I'm not sure what was happening before but if you feel she is really sleepy and your mommy instincts are concerned; If she's feeding for a lot less than 10 minutes or not waking up to feed at all; If she's not having around 6 wet nappies in 24 hours then you could seek more help. In 10 minutes on one side I would say it is likely she is getting enough and reaching the hindmilk although this will depend on things like her latch and her feeding technique. Can you hear any reassuring swallowing?
In conclusion, a 2 week old baby who sleeps A LOT, falls asleep feeding, goes 2.5 hours between feeds and wakes several times in the night is called NORMAL. In fact if you're getting 2.5 hours in the day and 3-4 hours at night I call that good! At 2 weeks it's not easy for everyone to develop a predictable pattern. You can still expect things to change and growth spurts especially send things for a loop.
See how this growth spurt goes on. Give it a few days before you feel her previous pattern has gone forever. Whatever it was, it must have been pretty good. The description of your terrible night and her feeding pattern today is normal for many.
And congratulations on the new arrival.
