I think worrying is completely natural, especially if you've had losses yourself or are aware of risks from those close to you.
Two of my friends have had still births and I have had a second trimester loss. I feel super aware of things that can happen and am constantly terrified, particularly of the 20 week scan as this is where things went wrong for us last time. I've also had a bleed this pregnancy at 14 weeks (currently 15+4).
I think the best thing is taking the pregnancy a day at a time, I have to remind myself that right now, at this moment I have no reason to think anything is wrong with my baby, ultimately worrying won't help baby and unfortunately what will be will be which sucks.
Good luck xx