Irregular periods wat do i do?

hey der.. k ive been ttc 4 6/7 months, but i cant get preg cuz i do tink am ovualatin wen am not.. d second last period i got was on d 3rd of march and d last one on d 16th of april. is it normall???? lik 45 days ... i dunno wats up wit me.. and if i get a ovualation test how wil i no wen ta tak it plz help me cuz am just losin hope and feelin so down bout dis