What are some reason id be nauseated, dizzy, tired, and sjort of breath?

See your doctor. It would have been helpful if you'd provided more info, including your age, medical history and medications you may be taking. However, what you are describing could be due to cardiac causes, including atrial fibrillation, heart failure, angina or even heart attack. It could also be due to infectious causes like pneumonia. Medication side effects or allergies are also possible. Go see your doctor!
Could be serious. These can be serious symptoms of heart disease (such as coronary disease, heart attack or heart failure). I would recommend you see your medical provider as soon as possible.