Body change :(

I have always been a little self-conscious since I was young. I feel afraid, nervous about how my body will be after my pregnancy. My mother got really bad stretch marks, and my sister also. Obesity does run in my family on my mother's side. I have fears of becoming that way and having stretch marks. :( I'm 5'8 and usually between 145-50 lbs. Right now at 8.3 weeks I'm 146.