TTC after Mirena

My husband and I are TTC but have yet to have a positive pregnancy test. I was on Mirena for 5 years, had it removed in January, and have been having irregular periods. It's been hard to track my cycle but we have a fairly active sex life and am just shocked nothing has happened yet. I already have a 6 year old daughter, normal pregnancy, and have had an ultrasound done on my cervix and olvaries everything looking normal. Any advice or similar stories?