Diesel Bombers - 2006 white smoke.

Hey guys so I hadnt driven my truck in 3 or 4 days, and It wasn't too cold out but it was warm either, got below freezing at night but then got up to 50 during the day. Anyways when i started it up to take it to the shop yesterday, a crap load of white smoke came out the exhaust and it slowly dissipated to more of blue/white haze, when I picked it up from the shop today it was still shooting out a white/blue haze not much but a little. Just wondering what you guys thought? Was it just because it was cold and hadn't been started it a couple days? It seemed like it ran and drove fine.