How To Determine Fertile Period With Irregular Bleeding Pattern

hello dr.

i m swetha. im 21 n married..

i had pco when i was 18 n got treated from a gynec after which i had periods after 42 days without medications..

but nw even after marriage i hav dis problem of delayed periods n because of dis i couldn confirm my fertile days n so couldn get pregnent too...

what shld i do nw..cos now i m in germany.whereas i took treatment when i was in india...