Hi Reethi,
Re your comments:-
"Yes maybe I should go back and ask for some tests".
There is no maybe, you need to have some blood tests done. As your cycle is irregular these can be done according to calendar days. You need a day 3 (this measures LH and FSH) and a day 21 test (that measures progesterone).
"My cycle has always been irregular, it is only regular when I am on the pill.
Snap!!. Even more reason to my mind to get a referral in my view.
The pill if anything can mask symptoms of the underlying problem. The pill bleed is not an ovulatory one; it happens as a result of stopping the hormonal pill.
Snap again!. In my case my irregular periods were caused by PCOS.
"I think I will buy that book as I tend to have an idea by body changes as to when I might be ovulating but I thought that you needed to have sex before you ovulate (my words here - NO!) so I think I need to educate myself as I'm probably having sex on the wrong days anyway".
Don't buy into this idea that you're having sex on the wrong days!. Any rigourous timing of intercourse is a mistake and can do more harm than good. If your periods are not regular then you are likely to be not ovulating. I would suggest as well you don't buy the "taking charge of your fertility" book purely and simply because your periods are irregular. It will not help in such circumstances.
You need answers, don't delay any longer.
Attila