Become speechless in the middle of something...why?

Hi dear, It happened me at many times. If I get tensed, it will definitely will happen to me. Some seminars, when I am in the plat forms, or in a crowd for a speech, or in a discussion meeting, etc. it happens and after everything over, I will get a flow of words and so on. I normally curse the situation when it happens. Sometimes if we have more than one option, or different opinions, many options and such situations also we will be in a position to which way to move. Also, we are the main person and we are supposed to give an immediate response and by the time we will become dumb – it become absolutely a painful situation – but we can resolve the same by tackling the situaiton with w slight break or changing the subject or reconstructing the sentence with some example, etc. However, whatever it may be, the situation really last for only few second – but it really annoys at certain times. Regards, Thank-s

yeah....usually when i'm tired of haven't had enough sleep the night before, my mind functions a little bit slow...and makes me speechless at times.... sometimes i talk too fast and then suddenly i lose my own trail of thought and get lost in what i was saying.... it could be embarrassing sometimes.