I had the exact same deal with my DD, we'd be up ALL night I would dread sun down. What worked for us was the same as the other ladies suggestions, I would wake her at 7am regardless of what had happened overnight, open all of the blinds in the house and start the day. She would nap with the blinds open too. Then I started a bedtime routine of bath, dim lighting, singing, feed in her dark room then bed. Overnight for feeds and nappy changes I'd keep it business like, no chating or eye contact only a night light on, it only took a couple of days and she's worked it out. Hang in there!