I have been delayed my mestration period for 5 years? what is the possible cause and what should i do?

Unsure: From your question I'm not sure whether your cycles have been longer than usual for 5 years or you haven't had a period in 5 years. The causes are very different. You could just naturally have a longer cycle. Up to 35-42 days (depending on your source) can be perfectly normal. 5 years is not. See your doctor for a full history,exam, and appropriate testing to know for sure what the problem is.