I am on the pill, but could I be pregnant?

Okay, so I started taking the combined pill (Microgynon 30ED) on 12th January- this was also the day of my first period.. Although I started taking it at 7pm that night, so had endured a normal period throughout that day. I still had a very light bleed that night and the morning of the next day (13th January) but this soon came to a halt. I have carried on taking it 7pm on the dot every night.. On the 21st January, (after 9 days of being on the pill) I had unprotected with my boyfriend- he did NOT and it was only for a short duration of time. Slightly devious, we went to the pharmacist and explained the situation and she said we were absolutely fine. We then had it again on the 22nd and 23rd- again, he did NOT . Even thought the pharmacist has reured us, I am still very wary. Could I be pregnant?