On the basis of probability your cycle will revert to normal again over the coming cycle. I don’t think you need to do anything for now unless you develop further symptoms that are troubling you. The whole process that regulates periods is subject to a diverse range of influences. For example the cycle may be disrupted in the case of recent illness, a major shock or distressing experience, anticipation of a job interview, waiting for exam results or international travel. Even worrying about it can disrupt the menstrual cycle. With the advent of the contraceptive pill the notion of clockwork regularity for the menstrual cycle has become firmly established in many women’s minds. Some people now think that if you don’t have a regular 28-day cycle there must be something wrong. It is perfectly normal for a woman to have an occasional period that does not conform to her usual pattern.