Why am I not showing?

I am 22 weeks and 2 days, and I went to the dr at exactly 22 weeks to review my anatomy exam, and my dr informed me that I have a healthy and huge baby! She has always measured 2 weeks ahead of what she actually is. She said that if she keeps growing at this rate, she expects me to be delivering a 10lb baby! All of this amazed me because I don’t even have a real baby bump yet. I’m not a small girl either. I like to say my butt looks more pregnant then my stomach does🙄😂 but my stomach has always been flat! These days it just looks like I’m full all the time and I just had a big meal lol. This is my first pregnancy also. I know it sounds silly and I shouldn’t compare my belly to others, it just has me curious as to how I have such a big baby and no baby bump at 22 weeks?!