I have been facing one too many of those weeks of late. At times, it comes in moments, sometimes days. It sure is mind boggling going through this. At times I feel like I'm finally getting a grip on my speech and then one fine day, bam! It feels like I can't say the most simplest of words. What keeps me going is that the general trend is better. Therapy has helped me a lot. I still have those days. But I see them as variations in the graph. One thing I try and do in such moments is to just stop. Empty my mind and the general feeling of "this week sucks". Take a deep breath, apply therapy and try again. Maybe just go for a walk, talk to random people, ask them the time, direction, etc. anything to lift your mood from that rut. The graph of my speech was at it's nadir before. I was what you call a severe stutterer. But I have improved a lot, the graph may vary and bobble even now, but it does that a much higher scale than before. Hope this helps. Continue sharing! And most of all, share your successes! Soon you'll realise that you have many.