WORRIED!

I'm currently 4w3d and it seems all I read about on here is miscarriages. This is my first pregnancy and confident I won't have one but it's hard to stay at peace when that's all I read/hear about. Does a lot of first pregnancys end in miscarriage?? I go for my first ultrasound at the end of this month and I really want to hear my babies heartbeat. How do you all stay positive??