Weird feelings inside...?

Hey all, I am around 11.5 weeks along. I work in an office setting so i spend alot of my day seated. I have been getting a weird feeling every once in a while.. like butterflies or quickening. Is it too early to feel baby? Could it most likely be gas?

Also, is anyone having the feeling like they can feel their ribs are widening? Or that your body is shifting around? I cant pin point exactly the feeling 😅...