Hello. I was a regular cannabis smoker in the past with no problems. About a week ago I was smoking and immediately afterwards I began experiencing a fast heart rate and extreme difficulty breathing, similar to that of a panic attack. Since then I’ve had trouble breathing on a daily basis, extremely high heart rate when engaged in everyday activities, and also pain across my chest, in my left shoulder and on my back. The symptoms are beginning to get worse and i’m getting worried. Do you think this could be anxiety related or something more serious?