It may be because an accumulation of speaking experiences that you perceive as negative, are causing you to block more. You have to use the power of reframing the way you see each day with a positive attitude to create positive momentum. Because you might be speaking while at the same time being influenced by these negative memories. You gotta treat every moment like it’s a new moment. You’re seeing each day the in the same negative way because you keep using the same point of reference. Try using a different point of reference mentally. Because our world often isn’t what changes, it’s our mind that changes the way we see the world. Not to sound tacky or anything but it’s true