3 week old feeding and sleep issues

My 3 week old is refusing to stay down to sleep. The longest she slept yesterday was for 2.5 hours in her car seat, and the rest were small naps lasting between 5 to 30 minutes.She will nurse for 10-40 mins, burp and remain upright but asleep for 20 mins, and then I'll set her in her crib. The thing is, she'll wake up and automatically start screaming for food. There's little whining or any other noises before, she just wakes up and screams. I'll change her if she needs it, try to calm her and then nurse her, but she's usually still full from her previous feeding. I try to burp her every 10 mins to reduce the chances of vomiting, but as soon as I unlatch her, she screams.She's been great up until now about sleeping in her crib, and used to only wake up 2-3 times per night. But it's 1:30am and she's been doing this since 5:30am yesterday.What do I do to get her sleeping again? She looks so exhausted.Edit: just adding that co-sleeping makes me extremely nervous, so I don't consider it an option. Also, when she wakes up, it doesn't matter how long she was asleep for, she acts as though she hasn't eaten in several hours, even though it's usually only been 20 minutes. via /r/Parenting http://ift.tt/2duDyx6