Marijuana abused to self medicate is frankly cheaper than paying for mental health medication and therapy. It's also fast acting and has only minor negative side effects as opposed to taking several weeks to take effect and for any negative side effects (these can be rather bothersome or bad) to go away. Not to mention that's if that particular medication works for you. Going through several types, change in doses, etc can go on for a year or more easily.

In my experience however, withdrawal only takes a few days, I don't recall being any more irritable than before except that marijuana makes me less prone to irritations to begin with, and the thing that's the worst is the boredom.

It's what do you do with your time? Work can keep you occupied and busy, but at home the activities you are likely going to do you did with marijuana. Video games and television/movies are harder to 'feel' interested in. Eating high is just really enjoyable. And trying to sleep is difficult especially when you know you could just smoke some pot and drift off instead of being too bored and restless to sleep.