Thanks for query,
You have a delayed period due to hormonal
imbalance.This occurs due to tension ,Anxiety
,Late hours of working,Shift duty or any pathology of ovary.
Your symptoms of nausea & tiredness
may be due to your delayed period.
Your low iron level also needs treatment as this is also one of the reason for your tiredness.
You should avoid eating high cholesterol
diet like oil fat junk food etc.If needed ask your doctor for cholesterol lowering medicine.