periods after the pill

Hi all, my husband and I have decided to try for a baby. I have been on the pill (microgynon) the whole time we have been together so 11years. I took my last pill on 28th August had a period from 2nd-4th September and nothing since. 
I had expected to get a period last Thursday 29th /Friday 30th. I took 2 pregnancy test at the weekend- both negative. 
Is it normal for periods to take a while to get back into a cycle? 
Thanks