Adding Fermentables

AAHHHH... Panic Panic..

For some reason my efficiency dramatically dropped for this batch of beer and ended up with a reading of 1.035... Should have been 1.058.

I've already pitched the yeast about 24 hours ago and now I'm wondering if I should or can add additional fermentables "corn sugar".

It was my first attempt at a pilsner and never worked with such a light beer.

If you do recommend that I add fermentables.. should it be done NOW or once I transfer to secondary for lagering?

Eek. Don't add so much corn sugar to bring you up 23 points. It will raise the gravity, but taste terrible. If you're happy with a session beer, keep it as is. If not, pull half gallon to a gallon of weak wort, bring it to light boil and add a couple pounds of dme. Let it cool and mix back into your fermentor. You should do this sooner rather than later.