getting insecure

I know some women get sensitive over this subject because I should be happy I'm pregnant which I am. But I am getting insecure about my body. I'm 28 weeks, obviously I'll keep growing. I just feel like my bump is going to look weird because I'm already carrying low. And I'm starting to see very light stretch marks. So I know they'll get darker as well. And I just keep thinking my stomach will never be the same again. And this whole time I haven't gained weight besides in my stomach. My legs are till twigs which I hate. It's just different for me because I just turned 21 and always been this petite girl with a flat stomach. Even now my boyfriend rarely has sex with me, and I always keep my shirt on when we do. And I think it'll be that way forever. And I use to never be afraid to be complelty naked in front of him. I really don't mean to sound ungrateful because I'm over the moon about being pregnant and can't wait to be a mom. but it is upsetting being young and feeling, pretty much knowing I'm never going to look the same and I'm just so insecure. 😞