Some women dont gain much weight. Everybody is different . You'll show when baby is bigger. Gaining unhealthy weight will not give you a baby bump. Just wait and maybe in 5 weeks you'll start to show. I was 19 weeks when I got my little bump.
Of course you'll gain weight. Your so early in pregnancy you prolly havent even gain any right now but you'll definitely gain a lot just be patient
You are still very early in pregnancy . just eat normally and you will be fine. Dont worry about putting on weight just yet. You will gain a ton later