I think many here are in the same boat, so to speak. XNA was great and I had a lot of fun, now I'm moving on as Microsoft is keeping too silent about it, and excluding it in the ways you already noticed.
There's a workaround to develop XNA projects with Visual Studio 2012 and they should still run on Windows 8 desktop, but there's no official support from Microsoft.
Look at other frameworks/wrappers for .NET/C# like SlimDX if you want to continue this route.
Microsoft seems to want to focus on native code now, it almost feels like a revival movement from within the company, with C++ and DirectX being the combo of choice, even on their Windows Phone 8 platform.
Me myself am completely refocusing on
- using existing game engine for serious game development projects, like UDK and Unity
- switching to HTML+Javascript for hobby game tinkering, with C# on the backend (currently using SignalR) and I'm having a blast, especially with ReSharper 7.0 and JSLint as a R# plugin ^^
Some additional rambling: I'm contemplating C++11 now and then as this seems the new old Microsoft way but I never really did like C++ to begin with, especially after being exposed to languages like Java an C#, so I feel a bit spoiled. Also, JavaScript turned out to be much less of an ugly language after reading through The Best Parts and getting seriously into web front-end work in my career again, I feel the powerful ways of expressing myself in JavaScript really makes me smile these days, and there are JavaScript+WebGL demo and intro compos at demoparties these days - doing very cool stuff.