I would recommend trying a different strain and/or different dosage. I do work while on MJ totally fine, and in fact, I notice some more abstract programming I think about differently (only word I could think of that didn't have a positive/negative bias). Edibles could also provide another type of feeling for you, but again, I would start with a smaller dose than recommended by most. Obviously this is all anecdotal. Best of luck if you try it again!

Also, comparing "addiction, physical dependence, and potentially a life-ruining downward spiral of misery" and your feeling over "worthless and incapable of doing anything constructive" seem so bizarrely juxtaposed that I'm not even sure you weren't being sarcastic.