Ob-Gyn questions? Ask a gynecologist online.
the problem you describe is very likely caused by a harmless hormonal imbalance which can occur due to many effects, even stress or climate changes can play a role. I would recommend the use of monk´s pepper (Vitex agnus-castus, OTC at pharmacy), which can regulate the cycle. If this doesn´t succeed, you should visit your OB/GYN, he then can resolve the problem by prescribing a hormonal medicament (gestagen) which has to be taken for 10 days.
Please don´t forget to honour my work with a kindly rating (3-5 stars).Thanks a lot, all the best for you,Dr. N. Scheufele