You're obviously learning the hard way, but there's two good lessons here: keep your windscreen clean, and don't drive so close behind the car in front that you can't stop in a hurry. Failing to do so is careless whether you're a learner or not. In fact as a learner you need to be more careful than other drivers until you get a lot more practice in and react more automatically. You're in the hands of the police now. Personally I think you'd been punished enough, but I couldn't entirely blame them if they thought otherwise; what happened could have been a lot worse if, say, people in the other car had been hurt.