From what I remember, it takes them a few weeks to get the day and night thing sorted out. I know Jenna was most active inside me from about 5:30pm onwards, so you can expect that a similar pattern will develop outside the womb for a little while.
They call it "arsenic" or "witching hour". Jenna's was about 12-2am for the first few weeks, and slowly it dropped back to about 5pm. There will always be an unsettled time during the 24hr period.

The best thing you can do is try to catch some zzzz's during the day so the night wake-ups dont kill you in the first few days. Also feeding as much as you can will be great for bubs. Co-sleeping is great, but I did find that attachment was so important in those first few weeks when your nipples are still soft, and their mouth is so pinchy!! So juts make sure when you are feeding bubs in bed, they stay nice and tight against your body. That way you should avoid the nasty crack I got when Jenna was about 2 weeks old..... OUCH!!!

Have fun, and remember, the first 6 weeks is purely about survival. If you can get through that, anyway you can I might add, the rest seems relatively easy. Goodluck, and you are ding a great job!!

Fi