I'd say she's just still used to being on the inside.... and often times the rocking of you moving around during the day is enough to rock them to sleep and when you lay down at night its up n' atom time in the belly. Surely it must take longer than a few weeks to get them regulated.... I would do as the others suggested and make daylight more obvious and sleeptime at night quieter. When you get up to feed, just do it quietly without lights etc, and gently rock back to sleep. I co-slept when they were little babes myself because I got more sleep that way, I found I was able to feed & fall back asleep and the baby would as well... when I moved them into a hammock or cot, they were much older and knew day from night.

its hard work in the first trimester earthside....