Hi!
Your body is probably still trying to regulate after discontinuing the pills. It is fairly common for the first few cycles to be irregular. Also, if your periods were irregular before you went on pills, it will very likely be irregular again when you are off them.
One thing I sometimes do in this type of case is to give the patient 5 days of Prometrium.
Infertility doctors sometimes use this drug to support a pregnancy, preventing miscarriage. If you are not pregnant it will induce your period so you can move on to the next ovulation and try again. If you are pregnant, nothing will happen, and you can repeat your pregnancy test.
Don't get too frustrated--stress is counter-productive when you are trying to conceive!
Good luck!
Dr B
Did you have a blood test?