Fatigue feels like constant tiredness. It can include a lack of energy, difficulty concentrating and a lack of motivation. Fatigue can be caused by illness and treatments (eg some tablets and liquid medicines). It can also be related to poor eating or sleeping patterns.
Most people want to rest when they feel fatigued. However, fatigue can sometimes be improved by exercise or activity that suits your situation and ability (eg going for a short walk with your family when they visit). Other things likely to help are eating a healthy diet, drinking plenty of fluids and sleeping well.