According to quit s*****g weed guide produced by the university of Notre Dame

It takes about a week for the THC content of one weed cigarette (or
joint) to leave your body and for heavy users, you can begin to expect feeling withdrawal symptoms 3 weeks after your last dose.
The National Institute on Drug Abuse lists as withdrawal symptom of quitting weed the following:

**irritability

** mood swings

** Anxiety

** Headaches

** stomach pain

** insomnia

** Reduced appetite

A whole cascade of symptoms follows from the ones already mentioned and just like with quitting s*****g cold turkey, you will probably have to fight a battle against your cravings for weed. This is what will usually cause you to become irritable and anxious.
Your body not getting any THC will affect your sleep patterns as well, so you might not be able to get a good night’s rest. This is a common one with weed smokers, since a lot of weed smokers like to light one up right before going to bed, so they can sleep better. But, just like with any sleeping p**l, if you take it away then you can be sure that your sleep will be affected.
Less sleep can reduce performance at work or school and lead to a loss of motivation to do anything. Eventually leading right back to where we started: irritability.
It is important to remember however that despite the realness of these symptoms they are not long-lasting or life-threatening. The National Institute on Drug Abuse even states that “some people having m*******a withdrawal might not realize it”.
Withdrawal symptoms from quitting weed s*****g typically last only for a few days or, at most, weeks and once the initial feelings of anxiety and irritability pass there are some other things that might start to happen. If you were a long-time weed smoker the very act of s*****g weed became, over time, ritualized and your body starts to crave not only THC but the environmental factors (such as the touch and feel and a smell of m*******a) that accompany it.
As Dr. Stuart Gitlow a professor at the University of Florida states about quitting weed, “there’s a familiarity with an experience that now will be missed”. This sudden emptiness, which is a more subtle withdrawal symptom, might allow ex-users to begin to explore more fully the reasons why they stopped or even why they started. Dr. Gitlow describes this post-withdrawal phase as when ex-users begin to “feel feelings again”.
Despite the physical withdrawal symptoms of quitting weed only lasting a few weeks, Dr. Gitlow cautions that getting used to the “new reality” of quitting weed s*****g can be a process that lasts up to a year. While the more immediate withdrawal symptoms such as insomnia and irritability dissipate within a few days, the more deep-seeded psychological problems of habitual weed s*****g or any abuse of a substance can persist and in that case, further therapy should be pursued and observed.