Could I be pregnant while ultrasound scan showed multiple follices?

[Eps2000]

I had sex on 19 June with my boyfriend. We are 17 and it was our first time. We used a condom but I was not on the pills.

Last Thursday I went to a gynecologist for a vaginal ultrasound scan since I have always had irregular periods; the scan showed a big follicle surrounded by group of smaller follicles - the doctor suspected it could be polycystic ovary syndrome (PCO).

So, about pregnancy: my last period started on 12 June and ended 17 June; I have not had another one yet. It could be that I am not ovulating this month due to PCO; I am aware that chances of conception after period are slim, especially when we used the condom. But, is it medically possible to be pregnant while ultrasound shows a mature follicle and other immature ones? Am I being obsessive over safety or should I be concerned to get a home pregnancy test, just to be sure.

Lastly, will PCO affect effectiveness of birth control pills? (21 days, rigevidon)

I have talked to my boyfriend but at the moment he is away. We have been together for 2 years and we want to be as safe as possible. I cannot share this with my parents and I am in a country where being under 17 means GPs have the right to call up your parents. Any help is appreciated.

[remar]

As long as the condom was used properly and you did not have a failure like a break or tear then you are not pregnant. Condoms work so very well to prevent pregnancy if they're used properly. No, I would say that you are for sure not pregnant.

[Eps2000]

Edit: I meant under 18*** I did not specifically consult the doctor about chances of pregnancy. I asked for a pregnancy test but the nurse said that I already had a ultrasound scan and there was no need for a pregnancy test. (egg is microscopic and not detectable before 5 weeks? except if presence of mature follicles indicate impossibility of pregnancy...?)