So I know it wasn't that long ago I posted about how to keep a newborn awake longer. lol. Of course, NOW my problem is getting her to sleep!

K is 3.5 weeks old and the past week she's been getting increasingly alert and so difficult to get to sleep! She's actually always been difficult to get asleep AND stay asleep. But the past several days, she will go periods of 5-6 hours awake in the afternoon and/or evening!
i.e. Today I have fed her 4 times and she's been awake since 11 am till now 4:30 pm. She may fall asleep for a few minutes in my arms, but ANY movement and she's up, blinking, then staring at me. I think the longest period she's slept today has been maybe 20 min.! Is this normal so young?
She wants me to hold her all the time, but I can't sit down (except for now, I've discovered, bouncing on my yoga ball). She doesn't like sitting in the swing for more than a couple of minutes, unless she's already passed out completely when I put her in it. Now that she's asleep, I'm off to go buy a bouncy chair to save my poor arms and back!
Is it crazy that she can stay awake for such long periods already?!