It is not the end of the world if you did not end up in Northwest, and life isn't over just because you got lost and missed your advising appointment. There is no sense in stressing over the little things for which you have no control over.
Most likely a lot of them. As humans we tend tend to think we are invincible and that bad things only happen to other people. However, the reality is that we are not immune from errors in judgment, and accidents happen. The best thing you can do is learn from each mistake, because that is what college is for: learning!
What you put out into the world has a way of coming back to you. The girl you helped find her way to the dining hall may be the same girl that gives you a ride to the mall so you don't have to walk in the rain. Even the smallest acts do not go unnoticed.
It is normal to feel pressured to act a certain way or say certain things to get people to like you, but it is better to stay true to yourself in order to surround yourself with the right kind of friends.
While you may be entering a new stage of independence and adulthood, that does not mean that you won't still find yourself missing your mom and dad. When you're feeling especially homesick (which you will from time to time), don't hesitate to pick up the phone. Your parents will love hearing from you and be reassured to know that they are still needed.