Closterphobia of Stress

Every day, closterphobia breaks in to my subconcious. I don't notice it at first. Then, slowly, as the day goes on, I feel more like I'm suffocating. Each breath gets harder. I don't know why, but it happens. I can't seem to make it stop, it just... keeps coming back. I can't break free from its grasp, until I fall asleep. Sleep... the remedy for everything. When I wake up, my breathing is normal, I feel normal. But as the day goes on, the closterphobia returns.
Closterphobia, the fear of small spaces. My fear is being stuck in one spot in my life for too long, and never being able to break free. I want to have a life outside of school. I need to learn to balance my life better. But what can I do? How do I break free of the Closterphobia of Stress?