I've been feeling more tired and have some shortness of breath. when should i see the doctor?

Difficulty speaking: The most common cause of "difficulty speaking" is shortness of breath. This is usually a sign of serious illness including pneumonia, blood clot to lung, heart attack, asthma, heart failure, or other severe allergic reaction. You should see a doctor promptly for shortness of breath. Fatigue is a separate problem. Most people can cope with it if it is short-term; after 2 months, see a doctor.