a few tricks i came up with in the first days of my babys life:
when feeding during the day, stay in a well lit room withbackground nosie such as a fan, when its bedtime make it dark and quiet, dont talk to your LO too much jus make soft cooing or shh'ing noises
try swaddling for bedtime - this was a lifesaver for me in the first few days.
You said your milk came in, which is great news, things DO get easier from this point on (but when your LO is 3 weeks, the constant feeding willc ome back for growth spurt - be strong it gets a whole lot better after that!)
make sure your LO gets a good feed, if she starts to fall asleep use a baby wipe on her forehead o her neck to gently wake her up.
babies have very small tummys, they only can eat a small amount at one time, but their tummys empty very quickly. so it will feel like your constantly feeding till your LO is a bit older. it gets easier at the 1 month mark.
i know a lot of people here are for co-sleeping, im one of those who arent. I believe the risks are too great, thats my opinion, im sure the pro co-sleepers here will respect that as i respect their decisions too. But I am for feeding lying down on your bed (providing you can stay awake) once your LO is then asleep, leave her to sleep for a while *then* move her, baies hit REM sleep first and that is active sleep, its harder to move them in REM as tey wake easir, so let her sleep 15 minutes on the bed then move her to her own.
good luck and stay strong. trust me it gets more amazing EVERY day your baby gets older!