2 week old? Sounds normal to me.

Well, you could try waking her after a 2-3 hour day sleep and feed her and hope she switches the 4-5 hour stint to the night.

Co-sleeping means you can just feed her without waking up fully yourself and that will help you sleep better.

I found a mental outlook helped me: I didn't expect ANY sleep for a year, so if I had just an hour it was an hour more than expected so really good. After the first year it all went downhill because I needed sleep and expected it by then!

Best of luck to you.