Speech blockages vs stammer. Are they same?

Speech blockages vs stammer. Are they same? I’ve been wondering if these issues are related. It’s not that I can’t speak fluently, but I struggle with mental or speech blockages that make it difficult to articulate my thoughts clearly. When I’m put on the spot, I tend to freeze or react abruptly, unable to think beyond the immediate situation. My sentences become unstructured, and I end up sounding all over the place. It’s frustrating because I don’t see myself as someone with a typical stutter, but I suspect social anxiety might be a factor that triggers the issue. Have you ever experienced something similar? How can I improve or overcome this? Also, how can I develop skills like thinking on my feet and delivering under pressure? I appreciate you taking the time to read this!