That’s actually pretty good sleep for a two week old. Mine didn’t sleep that well until over a year 😩
Ok so first things first: the baby is actually sleeping well (very well!) so perhaps (and of course if you’ve been given medical advice then follow that) you could stop the expressing? Suckling increases supply much better than expressing, and not everyone expresses well. Plus it’s knackering you out. You’d be better spending that time sleeping.
All babies lose after birth, all of them. Unless they continue to lose or have lost too much then the best thing to do is to shove them on the breast more. If they are having wet nappies then they are feeding.
Go to bed with your baby - follow the safe cosleeping guidelines while she’s in there. You don’t have to cosleep if you dont want to - a sidecar crib is a brilliant halfway house. Just lie down safely and rest
The key is you rest and let the baby feed and that suckling boosts supply. Right now they are only tiny and they’re not going to drink loads at a sitting, nor are you guaranteed to pump loads. I was shit at pumping, never managed much and it was a waste for me. the best way to build up your milk is let the baby drive the demand
Learn to nurse lying on your side. Lie down safely with the baby and you can both doze and feed.
Your baby is actually sleeping brilliantly, what’s doing you in is the pressure to pump - and that is something you can probably stop.
If you’re feeling really anxious please do talk to your mw. Mine woke hourly for 18m and for a good seven months or so he woke every twenty mins and it nearly killed me.
Look after yourself, take the pumping pressure off and just go with the flow.