Brief Answer:
Need to consult for finding exact cause of the irregularity.

Detailed Answer:
Hi Huntermay62,
Thanks for asking.I have read your query & understand your concern.
*Plan B is a emergency contraceptive...having high level hormones...which act by postponing
ovulation (&so the pregnancy when it is taken).The action starts immediately after intake& lasts for about 8-10 days
- So after intake pregnancy is prevented.And after that the blood levelsof hormones fall. fall .This leads to withdrawal bleeding after 8-10 days of taking medicines&then the incomplete hormonal changes of disturbed menstrual cycles carry on.
-This causes delay in menstruation by 8-10 days,maximally by 15 days.The hormonal disturbance thus created is automatically corrected in following couple of months...not more than that.
*You had taken plan B 7months back&the periods are still irregular.This can not be due to plan B.
*The menstrual irregularity in such case can be due to some other reasons (general weakness,/ psychological stress/, hormoal imbalance ...ovarian,thyroid or pituitery glands problems./some uterine problems like cervical polyp,fibroid uterus...so pregnancy test is -ve.
** To solve this you need to undergo detailed physical examination by a gynecologist followed by specific confirmatory investigations&take specific treatment.
*** please consult a gynecologist/Endocrinologist.
I hope that helps you.Any follow up query is welcome.
Thanks.

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