Irregular Periods?

Does anyone else have irregular periods and know what the cause is? I honestly at one point in my life didn’t have a period for most likely a whole year. I was on the pill but I stopped taking it because it made me feel awful. An then I hadn’t seen a period in who knows how long. I thought I may have had cysts and wasn’t able to get pregnant. I did end up falling pregnant and had my son. When I did my checkups at the doctor she told me I did not have any cysts or anything like that. That I should get it further looked into. After my son was born I now have my period every other month. Anyone else have strange similarities?