I know a girl who suffered from severe endometriosis who had a child years after she had a weightloss surgery that was supposed to help with the pains with her endometriosis. She was about 30 before she ever was pregnant. You are 15. You do not need to have a baby. Have you thought how you are going to support it? How are you going to get a baby to the ER when there's a problem? You aren't old enough to drive. Please think this through, now may not be the right time in your life for a baby. Perhaps when you are older with means to support the child. I only say this because I know several girls struggling because they should have waited.
Stranger things have happened. I wouldn't rely on a medical condition as a reason for unprotected sex to be "safe." Unless a doctor has specifically told you it has rendered you infertile....
Of course, I would say at the very least it's safe to assume it would make it a lot harder to get pregnant. Still, protection of some sort is advised.