Family Planning Plus

If the sexual intercourse occurred during the first seven days after your Implanon insertion, Plan B use would have been recommended. Since you used the morning after pill within 24 hours of the condom breaking, you would have received its maximum protective effects. However, if the sex occurred more than seven days after having Implanon inserted, Plan B was not necessary. Implanon is extremely effective and provides continual protection against pregnancy for three years after insertion. Less than one woman out of 100 becomes pregnant during the first year of use. Condoms should be used in addition to Implanon during the first week. 

Menstrual irregularities are very common with both Implanon use and Plan B use. The spotting you are experiencing is normal. However, if you are concerned about pregnancy, wait 4-5 weeks and then take a preganncy test.