Personally, I wouldn't be worried. I had my first period post removal about a month later. It kind of depends on where you were in your body's cycle when it was removed (and it can be hard to really know the answer to that). Your hormones have been a mixture of synthetic and natural since having the IUD placed, and now your body needs to adjust. Anything could happen, so I would just relax and take notes on a calendar when you start. Hopefully a pattern will emerge sooner than later so you can predict things. Your body is programmed to regulate its cycles, but the IUD messed with that, so just give it time to figure it out again :)

Diana