I don't know how to return to animating because it all disappeared when I hit 0 and it went to perspective view.
Just hold middle mouse button and drag to rotate the view.
The 5 on your Numpad switches between perspective and orthographic view.
Numpad 0 switches into Camera view.
Numpad 1 Front View
Ctrl Numpad 1 Bottom View
Numpad 3 Right View
Ctrl Numpad 3 Left View
Numpad 7 Top View.
Ctrl Numpad 7 Bottom View