Depends on the IUD.
Mirena is hormonal... so it may or may not effect your sex drive. It, just like birth control pills, is not effective during antibiotic courses. No idea about nursing.
Paraguard is copper, and has no hormones at all. So no hormonal side effects (like sex drive, or menses shortening or legnthening -aka after the 1st couple of super crampy periods your periods are the same as when you were TTC). It doesn't effect nursing at all, again, because there are no hormones whatsoever. Also unlike Mirena, which has about the same failure rate as birth control pills when taken every day, paraguard has the same failure rate as a tubal ligation... and is also good the moment it is inserted (no waiting period)... and is NOT effected by antibiotics.
DO get muscle relaxers (otc midol, or Rx) for those first 2-3 periods, though. They're doozies.