Sudden and Significant weight loss, by all standards is a symptomatic of a serious health challenge which needs swift medical attention.
Major causes could be either or a combination of these:
1) HOMONAL IN BALANCE. Homones are mediators of several metabolic and physiological activities in human systems. Whatever happen , leading to their being inadequate or over secretions impacts anabolic and catabolic activities which would ultimately results into abnormal weight gain or loss.
2) MALNUTRITION. Inadequate supply of necessary energy , restoration and mediation nutrients would predispose to unexpected weight loss .It is therefore necessary to consciously ensure ingestion of food balanced in desired nutrients.
3) HYDRATION. Ensure adequate water intake continually. A dehydrated body will result in sudden weight loss ascwayer could account for as much as 60% of total body weight.
4)ORGANS FAILURE Failure of metabolic and Hydration organs like Kidney, Liver and Spleen could trigger sudden loss of weight as these organs controls the rates of nutrients intake and exit from the human system. Some Chronic diseases like Diabetes are symptomatic of organs damage.
Sudden wight loss is indeed aajor medical challenge which ought to be immediately reported to a professional medic for intervention.
Never self medicate . It portends more trouble than can be imagine.
Wouldn't you rather heed the foresaid; even as preventive media??
There could be many reason like change of diet, excessive excretion, may be because of some disease like thyroid or some other.
I suggest that you should consult with your doctor and have complete checkup and take it seriously.
Take care and have a good health.