i've been taking cerelle for around 2years, period can be anywhere between 2 weeks and 5 weeks apart and last anywhere between 3 days and 3 weeks. my last period was at the beginning of august & lasted almost 3 weeks, i haven't had another one since. i took a boots pregnancy test this morning as have been feeling exhausted & having sore nipples, the test was negative. does anyone have any ideas what could be going on?