Sex on ovulation day 11/15 took planb few hrs later that same day. (overweight so i figured pill might not work). got copper iud implanted 11/18. was it too late by then, and plan b affect the iud and not work? what chances of becoming preg?

IUD implanted late. But sometimes that itself can disrupt a pregnancy. Chances of being pregnant are unpredictable accurately. Best to get a preg. test to be sure.

The "Plan B" was taken appropriately, but is not 100% certain to prevent pregnancy. The "copper IUD" should prevent successful implantation of a fertilized egg if that should occur, however. Minimal chances of pregnancy, but if your period is delayed, obtain a serum HCG test to be certain about pregnancy.