B-shaped belly

So I’ve noticed my bump is basically a B shape. I’m actually underweight and this is my first baby, so I didn’t think I would have this? I’m so happy with my growing belly and I love what my body is doing for this baby, but the fact that my bump isn’t round is making me really self conscious. I thought maybe as I got further along it would round out, but I’m 18 weeks and it’s still like this.

Anyone else have this too? And does it ever round out later in pregnancy or is this just how it’s going to be for me?