I have to constantly sit down and catch my breath. Is this normal? I was active before these symptoms showed up.
A red flag. It's one thing to notice heavy breathing during activities that used to be quite routine. This can often be due to weight gain, or lack of exercise. However, when somebody has breathlessness to the point of having to sit to catch their breath, it's often a sign of a new medical problem. While heart and lung disease are the most common, anemia, hyperthyroidism and others must be considered as well.
Not normal. You may have problems with your lungs and/or heart. You should see your primary care physician who may lead you to a lung or heart internal doctor.
No that's not normal. New shortness of breath could be anemia, lung disease, heart disease, or even a blood clot in the lung, so it should be checked out immediately.