I dont know if this should be under teenage pregnancy or not, but I'm 18 and my last period was 2 weeks into October.
It sounds like you are in shock at the moment with lots of thoughts going round in your head. Your instincts seem to be saying that abortion doesn't feel comfortable, but then having a baby is scary with responsibilities that are overwhelming. You need your parents help and support, but you think they may react badly to the news.
I think it would help you to talk this through with someone. There are trained advisors on the helpline, or you can log into Online advisor. Once you have talked it through you may feel more confident to speak to your parents, or someone else you can trust to help and support you.