There are many causes of a delayed period, the ones most likely for you are:
* Psychogenic factors and Hormonal imbalance:
* Weight gain/loss
* Excessive dieting or overeating
* Hypothyroidism: hypothyroidism is a common cause of delayed periods and this can be the cause for you.
* Polycystic ovarian disease
A delayed or missed period is a very common condition due to slight hormonal imbalances caused by stress, exercise, weight gain or loss, etc. It will usually resolve spontaneously and you will get back your normal period.
However, it is medically recommended that if the period is delayed for more than 4 weeks, you should approach a gynaecologist for a check up. As it has been a month you can go for a Gynae checkup.
Meanwhile for now, steps you should take are:
Lots of fluids - water, juice, Gatorade.
Vt. C, Zinc and Vitamin B complex supplements -you can get this at your pharmacy.
Regular exercise - take 30 minutes of walk 5 times a week at the minimum. This is the most important step.
Maintain optimal weight – check your BMI on the net, its easily done. If you are overweight, try to reduce weight by at least 5 pounds, this will help greatly.
Avoid smoking, cut down on alcohol, cut down on caffeine
Cut down on excess sugar and carbs
High fiber diet -vegetables, fruits, non processed meat and fish - be sure to take nutritious diet
Regular hours of sleep
Dont obsess about this thing, it will only add to the stress and further delay your period even if you are not pregnant.
This will help to regularize the system, but since period is delayed by one month show your doctor for further investigations.