Talking with an HIV knowledgeable counselor or therapist may help determine how you are adjusting to your new diagnosis. Low testosterone can also be a factor. Even if this is only slightly low replacement therapy may help. Medication side effects are also a common cause for fatigue. Finally, HIV is, of course, a virus.
Viruses are well known to cause fatigue.
These are viral illnesses and they certainly cause fatigue along with other symptoms. Even common things like adequate rest, a good diet, and a regular exercise program can be quite helpful. Hope you get your energy level back soon. Thanks for writing. This is very common and most annoying problem.