No periods and 7 negative pregnacy tests

My friend took an ipill on 17th of march she has an irregular cycle of about 45-50 days... she got her periods within 20 days of taking the ipill but they were light and lasted for 3 days only... it has been two months since the last period and she still havent had her periods... she took 7 pregnancy tests in total one in the third week of april one in first week of may one in third week of may and 3 in 4th week of may and one in first week of june... all are negative still she doesnt have her periods... she is experiencing pms like soreness for the past 5 days cramps for the past 1 day but no periods... she is taking too much stress about this subject and is having a lot of anxiety please explain can be the reason