Thanks for the query.
If you had unprotected intercourse
around the time of pregnancy
then there is possibility of pregnancy.
In that case it can be implantation
bleeding. But just by spotting pregnancy cannot be confirmed or excluded.
While taking tablets also withdrawal bleeding can occur.
If you want to continue the pregnancy if present, better to stop the tablets.
And wait for few days, if your spotting do not turn into bleeding, go for pregnancy test once.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429