Brief Answer:
Hello dear. You require evaluation

Detailed Answer:
Hello dear. I understand your concern. So the causes of fatigue can be many at your age. It can be due to anemia, thyroid issues, liver disease, cardiovascular causes, chronic infection or may be related to cancer.

I would like to some more details like -
History of any swelling
Breathlessness
Chest pain
Any blood loss
Weight loss or gain etc.
Fever.

You will require following but not limited to these only investigations -

Complete blood counts
Liver function test
Kidney function test
Thyroid function test
Urine examination
Blood glucose.

Please revert back with reports
Thanks and Regards

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