Need Medication For Irregular Periods

hello doctor i am a 25 yr married female(1.5year).before my period was normal.now may b almost one year my perriod .irregular.before 5 month i taken medicine to regularise my period for 3 month..on the next month period came at correct time.but this my i dont hav period .i am not pregnant also.by these times we are planing for pregnancy.if my period again irregular what i will do?