Pregnancy on the brain??

I’m almost 30 weeks but it seemed even before I found out I was pregnant I have been beyond absent minded. To everyone it’s funny but I’ve had severe anxiety worrying about bring a parent to a newborn again. I have two girls (14 and 7 year old) and I’m pregnant with my first boy. Is it a pregnant thing when having a boy, a stress thing because I’m doing it all over again, or maybe that I’m 34 years old (feeling a little out of my prime to be having babies)? This pregnancy has been completely different compared to my other two.