Removed IUD and irregular periods?!

Am
I removed my IUD (mirena) in June and I have had extremely irregular periods ever since.  My dr said they should regulate right away if they were regular before I had the IUD inserted but last time I was two weeks late and am going on two weeks later than the adjusted period.  I went 3 years without periods because of the IUD and am wondering if this irregularity is normal or what?!  I'm TTC and having these late periods is messing with my head :-/. Thanks for any info!