Does losing weight rapidly and having night sweats can be likely caused by stress or Cancer?

My mom has been struggling with night sweats ever since she got COVID-19 because of mild heart pain ++ constipation with thin stool at times with bit of blood and mucus, she is also pre diabetes but thankfully never needed to take medicine for it

Stress / heart related issues
Cancer
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Does losing weight rapidly and having night sweats can be likely caused by stress or Cancer?
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