If you are feeding your baby, its normal to not have period provided pregnancy
is rule out.
Since after taking Primolut you did not menstruate then there can be likely possibility of pregnancy especially if you had unprotected intercourse
Before taking any other medication, you must rule out pregnancy with urine test for pregnancy.
In case its negative, you need to consult a gynecologist for appropriate medication.
If you have taken primolut only for one day then it is not the right way you have taken. Its taken minimum for 5 days. After primolut you ought to wait for your periods for about a week. If you do not menstruate after a week , then ruling out pregnancy is a must though you should have ruled out pregnancy before using primolut.