How long before I should worry

I started a batch of Austin Homebrew's Belgian Witbier yesterday. I used Wyeast's 3944 yeast since the home brew shop I visited didn't have whitelabs like the recipe calls for. Anyway I pitched the yeast at 6pm last night and this morning I still didn't have any activity. I shook the primary pail to try and get it going. Since this is my first experience with this yeast I am a bit nervous that it hasn't started fermenting. Wyeast's website said this could be a slow starting yeast and some may take 36 hours to show activity. How long should I wait before I get nervous? If I have to repitch I don't have any more witbier yeast or any HBS's close by that carry any.

RDWHAHB. You are long ways from worrying. Sometimes it takes 72 hours before noticeable fermentation.

If wyeast says 36 hours you definitely have no reason to worry before 36 hours. After 72 hours it's time to assess the situation.

Whenever I brew a batch, I usually see activity after a day. The last beer I did took almost 3 days. Don't sweat it. Plus, no activity in the airlock doesn't mean our little yeast buddies aren't alive and well.

If I read it right you used a liquid yeast with no starter?

You will be at least 3 days before you see active fermentation.

The yeast are having an Orgy right now to get their numbers up before they attack the evil sugars in your wort

7am this morning we have activity in the airlock. Hope it is as tasty as the last batch I made.