I Have Used Femilon For The First Time This Month

I have used Femilon for the first time this month .I am breastfeeding my 1st child.He is six months now.Will it reduce the milk supply?Also I had unprotected sex just a day after completing my 21 days tablets. Is there a risk of pregnancy in this case??Do i have to use other precautions from 22nd to 29th day?I did not have menstrual cycle after post natal period.Or do i start the new pack right away,it being 36hrs from 21st tablet. Please suggest.