I'm sorry to hear that you're experiencing these symptoms. Losing weight unintentionally, feeling warmth, having a mild fever around 100°F in the evening, along with ongoing weakness and tiredness, can be signs of an underlying health issue that needs attention.

Possible causes could include infections (such as tuberculosis or other chronic infections), inflammatory conditions, thyroid problems, or other systemic illnesses. Since these symptoms have persisted for over a month, it is important to have a thorough evaluation.

What you should do:

• Schedule an appointment with a primary care physician or an internal medicine specialist.
• They may perform a detailed history, physical examination, and order blood tests or imaging studies to identify the cause.
• If an infection or other specific condition is found, appropriate treatment can be started.

Please avoid self-medicating and seek professional medical advice promptly to ensure proper diagnosis and care. If symptoms worsen or you develop new symptoms like difficulty breathing, chest pain, or severe weakness, seek emergency care immediately.To narrow down potential causes, we will need some more information.Please tell me your age and gender. I understand you're concerned about losing weight, feeling warm, having a fever, and experiencing weakness. Providing your age and gender will help in understanding the possible causes.