some key sequence transform my text in outline

[Luca Ferrari <fluca1978@infinito.it>]

Hi,
I cannot understand exactly what I type, but this is what happened twice.
I was editing in the middle of a document, in particular within a "~"
block with a src block on the next line, as in the following:

I was editing ~here~
#+begin_src shell
....


Now, with some key sequence Org eated all the text below the cursor
position, transforming it into an outline block and therefore showing
me three dots. The problem is that I'm unable to expand it anymore
with TAB, and moreover I cannot delete it without killing the whole
outline itself. I'm sure I've not pressed the SHIFT+TAB sequence, that
apparently does the same but allows me to expand the outline, while
the one I'm getting is not expandable in the ordinary way.
I know this is not a detailed explaination, but I don't understand
exactly what I (wrongly) activated.
Any suggestion?

Thanks,
Luca