The data you provided (irregular menstrual period: light spotting for only one day) is not enough for a definitive diagnosis and its causes.
However, you might be experiencing hypomenorrhea, which is a condition in which the quantity of blood lost during menstrual period is decreased. There might be many causes for this condition, including: hormonal (changes in the blood level of the female sex hormones), constitutional (in some women it is quite normal to have less blood lost during the menstrual period and this occurs on every period). It might be caused by emotional stress that causes a hormonal imbalance. Certain other pathological conditions like Asherman’s syndrome might be causing this problem as well.


You are advised to visit your gynecologist for a physical examination and hormonal laboratory tests, which might reveal any hormonal imbalance. Your gynecologist might want to wait to see if this condition is transitory, but if it occurs again during the next period then adequate treatment according to the cause might be recommended (hormonal treatment might be recommended in case of a hormonal imbalance in order to induce a normal menstrual cycle and period).