I've been having a similar experience. I started smoking pretty much the beginning of my Freshman year of college and fell in love with it. I saw the world in a new, beautiful way. For most of the year, I kept my smoking habits under control. I usually only smoked on the weekends with friends. However, toward the end of my Freshman year, I started to smoke more and more. When summer came, and I was back home without much to do with a solid source of income, I started smoking everyday. I vowed that I would stop when college started again in the Fall. Needless to say, that didn't happen. I was surrounded by friends from the previous year who also started smoking everyday, and it became a vicious cycle from there. But at the time, I didn't think it was a bad thing; I still had all my friends from last year, and I was making more friends as well because of it. I was completely absorbed with the cannabis culture. In total, I smoked everyday for about 6 months.

But then one day, out of nowhere, I felt really depressed, and I didn't even know why. That night, I went for a walk and ended up crying for a while. But I still had no idea why, or why I was so depressed. The next few weeks, I became even more depressed. I started analyzing myself, and started realizing that weed was affecting my life, and I hadn't even known it. Hobbies and passions I once had had disappeared. I didn't do that much except sit around in my dorm getting high. Even though I still hung out with my friends a lot, I was always distant, and the focus was almost always weed. All the friends I made this semester were solely from weed. On top of that, I was constantly analyzing myself and my thoughts, and I was starting to feel depersonalized.

I realized that I wasn't using weed for the fun of it anymore like I was when I first started it. I was using it as an escape from reality. Smoking allowed my depression to fade away and allowed me to be happy. I was using it for all the wrong reasons.

Today is my 3rd day without trees. It's been rough, with the insomnia, depression, and mood swings that come with withdrawal, but I've already started feeling better. The feelings of depersonalization have already started to go away. My emotions are starting to feel less dulled. I've already stopped analyzing myself and my thoughts as much as I did when I was smoking. Being sober is actually extremely refreshing; I feel like I'm starting to look at the world in a new light again.

tl;dr:

My advice? Take a break. Maybe marijuana is making you depressed, maybe it isn't. In my case, I was using to mask was what I assume was existing depression, and that in turn made me even more depressed. There's nothing wrong with trees when used for the right reasons. Hell, some people are probably fine smoking everyday. More power to them. But for a lot of people, smoking that much is an unsustainable lifestyle. It was wearing me down mentally. Whatever you choose to do, good luck.