I just got one in Januray of this year. I had my last period then too. It is great!! I have not seen any Crohns related problems from the mirena.
I had a copper IUD for 10 years and opted for the 5 year mirena. The no-periods really helped my CD because I sometimes flared during that time of the month :)
Any questions you have let me know. I am happy I decided to get mirena.
Karen