Although weed is not physically addictive it can be psychologically addictive as you are experiencing. Basically you are quitting a habit and lifestyle that you have had for many years and that's hard to do. Focus on your goals understand what and why you are choosing to not smoke right now.

You may want to consider taking up some exercise, running, getting on a treadmill, basketball, whatever. It will help keep your mind off it. I found that going to a spa and doing a hot tub/sauna combo was very relaxing for me when I was getting clean for a job offer. An occasional massage didn't hurt either.

You will have some irritable days and some sleepless nights until you get used to not smoking daily. I went from a daily smoker, 1-2 joints a day to 1 -2 joints a week now. It can be done and I am very happy with the amount i smoke now.