I feel your pain bud, im currently on day 6 and i smoked nearly everyday for 7 and a half years. It was my everything, was never a fan of alcohol really, so anyways ive been going thru hell with imsomnia, not slept a wink. But dont think this will automatically happen for yourself because if you believe that it will probably happen, what the mind believes it believes. Dont turn to benzodiazepeines like i did, yeh it works like hell but all your doing is replacing one habit with another trust me. even a week of benzos you will be back to square one of no sleep. My advice is to go for some cardio training, try tire yourself out. Dont sleep during the day cos you will just fuck up your sleep pattern and itll be alot harder. Also dont be give in to cravings, i did at week 2 and trust me after that i had lost alot of tolerance and the high was particularly unpleasant (panic attacks, time slowed down) im glad i had the experience tho cos i has put me off weed for the rest of my life.
Tl;dr get lots of exerise, dont sleep during the day, no caffeine and dont give in to cravings or harder drugs, consider yourself lucky you arnt going thru heroin withdrawal in tandem(like i stupidly did)