It is likely that you have a progesterone deficiency syndrome. This occurs when the corpus luteum that is formed after ovulation fails to secrete adequate quantities of progesterone. As a result the endometrium lacks support, sloughs off and a period occurs.
If you are sure that you have ovulated, you will need to take progesterone tablets orally or vaginally for 10 days from the 16th to the 26th day of your cycle to regulate the cycle as well as be able to get pregnant.
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