early or clearing?

Hi, I've good grades but I'm still not sure whether I've done enough to get into the unis I've applied to. Is it the case that I may not be offered places frim some of my unis now but that I could be offered a place from them through clearing? If the same colleges lower their entry requirements during clearing could it also be the case that they would allow flexibility regarding grades now with the anticipation that they may not fill the places for that particular course during this initial round of offers?