There are many things that can cause fatigue... lack of exercise, lack of proper nutrition, caffeine usage, medications, anxiety, depression, stress, sleep, anemia, various diseases, etc, etc, etc. If you're transgender and looking to start T but not sure of what you can expect talk to your endo first and let them know about your fatigue. If you're not transgender and just looking to self diagnose here you should visit your regular Dr and discuss with them so they can make a proper diagnosis.