Having big dreams allows you to live in this fantasy of what life would look like if you achieved them. What no one tells you is achieving them doesn't mean that life stops. Life tends to go on no matter what dreams you achieve.
That being said it's easy to lose focus once you've gotten to where you want to be. You got into your dream school, were hired at your dream job, traveled to countries you've only ever heard of, and still, life hasn't stopped. It's just followed you wherever you've gone and sometimes it can get in the way of feeling the way you did when you received the acceptance letter to your dream college or booked the plane ticket to Paris.
In order to keep making new dreams and keep the same appreciation for achieving the ones you have, you need to sometimes be able to take a step outside of yourself. Occasionally at USC, I'm walking through campus and I'm so stuck in my head about the stresses and negatives that are going on in my life. But whenever that happens I take a second and I look around me and I remember the me I was three years ago going on a tour through my dream school. Walking in that big group of prospective students I could only see the positives. So when I'm bogged down about certain things going on in my life I remember that even though I've achieved getting into my dream school the dream's not over. I'm constantly living it.
Something that I and many others tend to forget is just because you're stressed about your relationship, classes, or just life, in general, doesn't mean the dream stops. If you lose sight of what you've worked tirelessly for, even for a second, refocus your perspective and your priorities and go from there.