My period was late by a week, only lasted a day with light flow

Hello, and thank you for sharing your question with the community.  I understand how worried you must be feeling right now.  I'd love to give you some useful information on the subject.

Irregular periods can happen for several reasons: taking medications, stress, little sleep, vigorous exercise, traveling, eating disorders, or hormonal imbalances to name a few.

Since your period started only 2 years ago, that is most likely the reason why it was late and then very brief.  During the first few years of getting a period it is common for them to be irregular sometimes because your hormones are still trying to reach a balanced state in order to regulate the cycle.  

Another common cause of irregular periods in young girls is a low iron count.  When your iron count is low, it is more difficult for the body to make the blood cells necessary to have a full period.  You can get a blood test to find out if your iron count is low, or simply take iron tablets.  

If you period continues to be irregular however, some doctors will suggest that you start taking birth control pills in order to help your periods stay regular.  Birth control pills contain hormones that help the body regulate your cycle so that it is consistent every month.

Let us know if you have any more questions.

Faith