Hello mam, thanks for trusting health care magic.
You should take that for 22 days in prescribed doses and let your period come and then again start it from 5th day of next cycle.
If possible get a pelvic ultrasound
and hormone assays viz Thyroid function tests
levels to see for the cause of this altered pattern of periods
In case you have further questions you can consult me on health care magic forum and i will be happy to help
Take care and wish you all the best.
Dr Manisha Jain.