I have recently been overtired and have required too much
Hello and welcome,
Fatigue can be due to many things. Among the most common causes of fatigue in a woman your age are anemia and hormonal fluctuations, if you are perimenopausal; poor quality sleep (from allergies, stress, apnea), and low thyroid levels.
Most illnesses are associated with fatigue, including diabetes. The aftermath of a viral infection can cause fatigue too. Overwork, stress, depression, anxiety can too. And not getting enough exercise. For some people even diet can cause fatigue such as having a lot of refined carbohydrates, high fructose corn sweetener, etc. And if a person normally has caffeinated products and stops these, there can be fatigue.
An evaluation usually starts with a complete blood count (to look for signs of infections, anemia), and a chemistry panel (which shows blood sugars and electrolytes). If the problem has been going on for weeks to months, a thyroid panel would also be in order.
I hope this information helps. Please let me know if I can provide further information or clarification.