I imagine that some trauma from the past has triggered this, AC. If you can pinpoint it and understand the cause and effect (including the learning effect and challenge for you, however painful the process) then I reckon you will progress. A good friend of mine had to spend long stretches of time alone as a very small child. This was the cause of her stuttering. She felt fearful and worthless. She now knows her intrinsic worth and her task in life she is a great singing instructor. Wishing you all the best on your path, which can be just as wonderful.