scared and worries

been trying for our rainbow baby since january this year, in october 2015 i gave birth at 24 weeks to our angel who we had to sadly make a choice for...due to servere abnormalities that i dont really want to go into, found out im finally pregnant again 3 days ago but im just so scared and worried the same thing is going to happen again. i couldnt bare going through all that again :( im a nervous wreck