Re: i only have my period every 4 months and im not on any pill...
There are too many reasons why one's period is irregular so, it is important that you go see a doctor. Don't be afraid to ask your dad. If he has paid any attention to women's reproductive health what-so-ever, he has to know that it is important for you to see an OBG-YN every year. So, you should have already been visiting one by now. Perhaps, don't even tell him the specific reason why you want to see an OB. Just tell him it is time to start seeing one. Is your Mom around? If he gives you any sort of trouble about going to an OB, perhaps talk to your Mom or another trusted older female in your life and have her discuss it with him. It is imperative that you go visit and OB every year for a Pap Smear and other annual checkups.
As far as the possible reasons for an irregular period...one may be your weight. Are you over or under weight? There are many other potential reasons for an irregular period and, you really need to find yours.
Please go to an OB. I think that when you first started your period was when you should have started visiting one.
Take care and keep in touch!