I have a light pink spotting 10 days after my unprotected intercourse and 8 days after i have taken the ecp. could this be implantation bleeding?

Implantation: Most often bleeding does not occur with implantation. When it does - it is usually a drop or two. Use of emergency contraception w/i 72 hrs makes pregnancy less likely. Emergency contraception symptoms can include spotting or bleeding, changes in menstrual flow or your period may be late or early. Take a home pregnancy test & notify your GYN if your period is 7 or > days late.

Implantation bleedin: As it is 8 days after emergency contraception and you used it within 48 hours of intercourse, this may be your period starting early. I would do a home pregnancy test to determine whether you are pregnant, however if you took the EPC when you said you did, you should not be pregnant.