Are you getting a hormonal or nonhormonal IUD? I did not react well to nexplanon (hormonal implant that goes into arm for 3 years) so I wanted a nonhormonal IUD so I wouldn't get horrible moodswings anymore. I can tell you all about hormonal IUDs.

I don't think you have to be off birth control before getting it. I had nexplanon taken out two weeks before getting my IUD and I could have had my IUD earlier if my ob/gyn was available before. I think you'll be fine but if you're getting the non-hormonal IUD, it works immediately so you can put off using birth control.

I really suggest you take the entire day off when you get it inserted and if the next day is still painful, take that day off too. But past those one or two days, you'll be fine. The insertion hurt, and the pain I felt afterwards felt like the most horrible cramps ever and it was significantly debilitating. I took the highest safest amount of midol/ibuprofen I could take and even then, it still hurt a lot and I ended up falling asleep to deal with the pain. The next day wasn't nearly as bad but I still had to take some pills so that it isn't as painful

After that though, nothing was as painful and I felt little "cramps" but I didn't have to take pills to deal with it.

As for periods, my period has only been regular for two cycles so far since I got my IUD (nexplanon had made it irregular) and so far, the periods are okay. They are more painful than my normal ones for the first two days but nothing some pills can't fix. On the third day, it can get very heavy (but not painful) and I have to take out my menstrual cup every two hours, and then the rest of my period is a regular flow and it can just a bit longer than 7 days (my normal period lasted 7 days, now it's a bit longer)