"zombie mode" -- I love this description! Mostly because it reminds me of Professor Quirrell, but still, it definitely describes how I feel when I'm in a procrastination/akrasia/depression cycle. I also have StayFocusd, which I find useful for automatically logging the amount of time I spend doing things I don't care about. It doesn't forcibly stop me from wandering (since it's simple enough to disable), but just knowing that I'm eating up my "leisure time" is enough to keep me doing things that are at least pseudo-productive.