Irregular periods

My periods are all over the place the last two augusts I didn't have a period there's nothing normal or regular idk when I'm supposed to start ever it's almost never on the same day, I've missed my period for December an that's never happened and I'm not stressed out. Please help I'm trying to see a doctor but haven't made a date yet. I want to get pregnant but idk how to start with the fact that my period is so annoying...