I was a heavy, all-day smoker for 10 years or so and smoked a little in the years preceding that.
I found I wanted to know what it was like to be clean and sober. I figured that I'd spent a lot of time smoking weed and I at least wanted to know what life was like without it. I figured I could always go back if I didn't like being clean.
The first days and months were kind of hard. It takes some time to adjust. It may help to google marijuana withdrawal symptoms so you know what you're facing, although they vary for everyone. As mentioned above on here, the vivid dreams are a common thing, but they get better after a week or two.
For a couple of months, I tended to feel kind of down and unmotivated a lot of the time. Exercise and eating well helps, but you just have to give your body a little time, after all, you've been smoking a LONG time and your body has adapted to it.
I have a long thread on here about my quit journey:
http://www.soberrecovery.com/forums/...wakenbake.html. I started by tapering down, but a lot of people recommend cold turkey. I think by about page 5 I finally made the leap and made my first whole day without smoking any. Now, I'm at almost 6 months weed-free!!
At first, it was hard to imagine that I'd ever make it. Now, I can't imagine going back. I feel so much calmer, less anxious and just stable. Plus, I enjoy not worrying about getting caught, not having to deal with pot head friends (nice, harmless people mostly, but just not going anywhere with their lives, as you mentioned). The extra money I have is a HUGE plus. It's nice to pay my bills and not go waste cash on weed. I even have money in savings now. And it's nice to have my head out of the cloud. It took a little time to get used to it, but it was so worth it.
Another link that really helped me both with weed and alcohol was the link on PAWS
Why We Don’t Get Better Immediately: Post-acute Withdrawal Syndrome (PAWS) | What...Me Sober?. It has some good info on why we don't immediately feel better after we quit and what we can do to speed up the healing process in our brains.