Suggest Remedies For Irregular Periods And Trouble In Conceiving

i have irregular periods and went to doctor .. she suggested me to drink lot of water and walk regularly.. and i did so it was regular but later when i missed my walking for few days because of illness again my periods was dragged... now we are planning for a kid so i am not able to get idea as to when i ovulate more and when is it right time to do? COULD U PLEASE HELP ME IN THIS