Not being able to donwload things or in some cases even just connect makes me sad.
That is all that needs to be said, really!!
The servers are overloading because of high traffic, presumably related to the launch of Pokemon Bank.
The problem with the eShop right now is that it's overloaded with holiday traffic. There's really nothing you can do except wait it out.
I know, I got a 3ds Xl for Christmas. I still can't even complete the system update which is preventing me from being able to trade Pokemon and can't access the 3ds shop to download Zelda. The problem is the server experienced overload and Nintendo is trying to fix it but they're still receiving a huge amount of traffic making things worse. They should just take the 3ds shop offline until they can fix the server.
That is particularly funny because I read some guy saying that the 3DS eShop was better than the Vita PSN store today. LoL
Well at least the store is functioning perfectly right now.
Honestly, it's almost as if they didn't expect this very obvious incident would happen.