I'm apprently bipolar (according to my dr, but him and i have differing opinions ) and i had been smoking daily for around the same amount of time as you. I was also doing opiates. I quit opiates(only to be back on them now trying to quit again) and then i quit weed. Quitting weed was harder than opiates IMO for the first 3 days. My moods were completely out of control, i think i tried to fight like 5 different friends in that 3 day time span. It's really hard because you feel crazy and have trouble convincing yourself the MJ is bad for you, while harder drugs have obvious consequences, weed's are more subtle. The good news is, IME you feel close to normal after a few days and after about a week i didn't even have the urge to smoke for the most part. Weed cravings weren't a big issue for me, after a bit of time passed i felt MUCHHH better without it, more creative, energetic, better memory, enjoyed things more, etc. i always thought it made things like TV, video games, and even working out better, but after being sober for awhile i can honestly say i enjoyed all aspects of life better than when i smoked.

This is all just my experience though, some people have had a harder time. I just wanted to share that i was/am in a similar boat as you and things worked out well(while i was sober). It definitely feels like letting go of a friend, i had my trusty vaporizer next to my bed for yearsss, packing it away was like moving on from something i held close to me in life. I think i used it as a way to feel like staying a kid and not move on from the past. Anyway, goodluck!!!