Pill and periods

So on August I got my period on the active pills on the 3rd week it lasted about 8 days . And now in September it's not coming yet and I'm already on the non active pills , and I have 4 days left to start my new pack . Is that okay ? Or should I be worried ? 
I've only been on the pill for two months August and September. When Started to take the pill I took it on a random day on August , because my period didn't come all July , so since I took it on a random day will my period skip a whole month before coming ?