Originally Posted by
Spartiate
Well, first of all, I don't think those things actually have an effect on the length of your dream, but rather on its vividness. The length of our dreams is determined by the length of our REM periods (which can't really be modified).
It is possible, however, that something wakes you up prematurely... You sound a bit stressed about the whole thing. Don't worry, relax, worrying about it is counterproductive (You already know what you need to do, just go with the flow and let your subconscious deal with it. If you force it, then it will likely fail.). When you become lucid, act like you have all the time in the world, don't feel rushed like if you needed to get a bunch of things done before it's over. The less emotional you get in a dream, the easier it is to control.