why so BIG?!

Hello! So, I'm pregnant with my 2nd but I had a small panick attack yesterday when I realized how much I'm already showing. I am tiny y'all. Pre-pregnancy test I weighed 110.4, its now what we think is week 5 and I'm still only weighing 111.5. I'm 4'11". Please tell me other mamas poked out right away and there aren't twins hiding in there. I didn't show until week 16 with my first.