Pressed the wrong hotkey. Camera blackout.

I pressed a bad button. Now, I want my camera view back!
When i press 0 it doesn’t go to camera view!
My view goes way up above the freegin scene, and everything looks black, for the most part. All i can see is the outline of an object and an x/y/z indicator, suggesting that a plane is selected. when i right-click on the dotted line, I expect the selection to go to camera. Instead, nothing. If I press G, I drag around a “plane” which is really a dot.
The plane that is selected is the ground!
When I grab it and move it, it’s just a little itty-bitty dot, so I zoom WAYYYYYY in!
Nothin’. Everything stays black.
When I hold ALT+left click and drag, BOOM! Everything appears.
What’s going on here? How do I fix it? I’d like to be able to see from my camera when I press numpad 0, please.

Maybe you pressed Ctrl-NUM0 on another object and made it the active camera, so when you press NUM0 your view changes to the view from the center of that object. Try selecting the camera and hitting Ctrl-NUM0 again.