Thanks for the query.
You have to get treated for the cause that is causing irregularity in periods.
Like poly cystic ovary disease, thyroid
abnormalities, anemia etc.
So, once the cause gets treated, the periods will get regularize automatically.
You better go for ultrasound
profile including thyroid profile, prolactin
With this possibly the cause for your problem can be identified and treatment can be given.
You have to maintain normal weight to your height.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429