I ran out of weed last week and went 7 days without smoking, due to my dealer being out of town for the weekend and then being dry when he came back for several days. I noticed no physical effects, I just wanted to smoke really bad for a while (yeah, I know, I'm psychologically addicted but I don't care). After a couple days though I just learned to accept the constant sobriety and was able to hold out until I got my sack. And boy, after seven days a little bit of THC can go a looooooong way.