The Life of a High School Burnout

I live in a constant state of panic. Am I smart enough? Did my period of depression and lack of motivation cost me my entire future? What school could possibly want me with only a 4.0 GPA?
The life of a high school burn out consists of an overloaded schedule, overworked mind, caffeine dependency, sleep deficiency. Is it even enough? I kill myself day after day with this busy schedule and these AP classes, but they just want more, more, more.
I am only one person, but they stretch us so thin to the point where I feel like I'm not even human, just a sheet of paper with numbers and activities.
It almost doesn't feel worth stressing so much about, but how can I not?
My mind is swarming with deadlines and test scores and application details, and these thoughts will not be quieted until I am enrolled in classes at a university.