Talk to Gynecologist on Irregular Menstrual Cycle

My age is 27 right now. In june 2019 i gave birth to my son. After 40 days my periods didnt stop for which doctor prescribed me Familia 3 months course after that i ask doctor for family planning as i want a gap so she recommend me femplant after that i started to had periods one week apart. I we t to doctor,did ultrasound everything was fine she said maybe its because body is adjusting to femplant it will take 3-6 months to get normal and she also gave me queen-f(similar to familia) for two weeks. As i was breastfeeding my son i only took it for seven days as it cause low milk supply. After that i didnt have periods for whole one year. Now again periods are coming week apart. Again gone through all ultrasounds they are all clear. Doctor said only some hormonal imbalance. Now if i take familia tablet daily its ok but if i stop taking medicine period come every seven days later. Now i had also weaned off my son so it should also not effect my hormones. Please guide me something. I a