I can tell you from personal experience that chasing your dreams is hard work. There are many ups and downs. There are many days when you want to quit. The best thing you can do is to take it one day at a time. Instead of focusing on the big changes you want to make, focus on waking up and doing what you have to do that day. You'll look up after a while and realize you're there.
To us high school students, everything feels like the absolute be-all and end-all. And I'll be the first to admit that I stress about the smallest things. But, after interning for Healthy Living I've realized I haven't taken any measures to try to alleviate that stress. So I'm starting now with a few things I've decided are just not worth my anxiety.