I keep having shortness of breath, light headed,and feeling like I can t stay up, very tired. It happens when I am getting up, walking or just standing. It feels like I have been running and can t catch my breath and huffing and puffing, I have been in the hospital and they have run test on my heart and lungs but could not find out why. I am diabetic, have arthritis, and nephropathy. I sweat a lot and have no energy.