I am 20 years old. My normal period started on 16 August. Then, only 10 days later, on 26 August, I started bleeding again. The bleeding was quite heavy for nearly the entire 7 days, and I am unsure whether it was a second period or abnormal bleeding. I have had no sexual intercourse since/before this, so pregnancy is not a possibility. I am not on birth control. It is now 27 September and I have not had another period. I have recently made some changes to my diet and exercise routine and my weight is around 61–62 kg. I take one
calcium +
vitamin tablet and a separate magnesium tablet. Could this be due to hormonal changes, and do I need any tests?