I just have one doubt that the qiyam that is there before ruku, if one doubts whether or not he has missed it then what he should do? For example at times when I wake up late for fajr and run short of time then I perform the prayer in hurry. At that time I have doubts that I misread the qiyam before ruku unintentionally maybe. In that case am I suppose to perform the prayer again because missing a wajib rukun intentionally or unintentionally invalidates the prayer? Also, I should mention that I have doubts even when I'm not in a hurry. I sometimes have doubt regarding the wajib standing that is there before ruku. Are we suppose to dismiss such doubts or start the prayer all over again?