First baby. Is it normal to worry about mis carrying?

Amber • 19 been with my fiancé for two yrs. pregnant with our first baby! Due febuary 27,2015!!(:
So this is my first baby and I am 8w5days and I worry about having a miscarriage. It runs in my family. Is it normal to worry about this or is it just me? I don't have my first sonogram until aug 4th. And I'm excited but scared at the same time because if i end up mis carrying it'll break my heart to pieces.