If you have always had regular 28-30 day cycles, never had this sort of menstrual disturbance before, are sexually active without any contraception
, please go ahead to test for pregnancy
. The bleeding could be a normal early period, ovulatory bleeding, a breakthrough bleeding
caused by hormonal imbalance; your symptoms suggest progesterone
effect and hence, the test for pregnancy. If pregnancy is excluded, you may wait for your next normal period and if this is also irregular, go for a proper evaluation by a specialist. Hope this helps.