Why does my path disappear when I add a new point?

[Lauren26672455up60]

I'm using my pen tool to outline the shape of my image, but after I add a new point in the middle to make triangles, the outline disappears.

[Ton Frederiks]

Guessing, is the path filled with white?

[Lauren26672455up60]

No, it looks like this. When I try to add another point, the path disappears. 

[Ton Frederiks]

Does the path have a stroke?

[Lauren26672455up60]

Yes

[Ton Frederiks]

Is it really gone, can you see it in Outline view (Cmd or Ctrl Y)?