It's like a fog, slowly forming overhead, and steadily getting thicker until it blocks out the sun.
Until everything becomes  duller than you remember, or just harder to do.
The one constant is the voice saying "What's the point?"

And I know this isn't the most brilliantly original description of depression - but bear with me here. I'm typing on regardless of the voice telling me this is a load of crap.

It's not unexpected.  Apparently lots of bereaved people get depression (who'd have thunk it?), and the good old Heart Manual even devotes a chapter to the depression you can expect following a heart attack.

It'll pass - it'll pass because it has to.  In the meantime bear with me.  I have been visiting your blogs you know - think of me as the one sitting huddled in the corner for now.