Irregular period / missed period. To.

Hai , I am frequently facing irregular periods from years but as i am taking pills of 21 days as suggested by doctors it's going good. And if in case I miss for one month it back to routine. Apart from that I have under gone laparoscopic surgery for cyst on the month of august 30. And on the month of September I got my periods naturally .. and October November with the use of tablets I got it . And with out tablet i got on December but it's very low flow . And this month also I didn't used tablets and I missed it .. I don't want to use the pills continuously to get my periods . As so far I'm also not diagnosed with pcod or pcos . But I m not sure why this is getting and I m really very frustrated .. whom to contact what to use and what not to .