I'm 5wks 3days pregnant, 1st pregnancy & my tummy is already looking bigger!

I'm 167cm tall and weigh 60kg - I am wondering how the hell my stomach could be poking out there already when I'm relatively tall, have a long torso and relatively fit as well! To those who don't know me, I wouldn't look pregnant - just a bit pudgy around the tummy!

When the baby is only like 2-3mm.... I just don't get how my stomach could be pokey already. My mum keeps saying "you might be having twins!" Geez I hope there's just 1 bubba in there or I think I'd die! Hahahahaha.....

So if the baby is only 2-3mm in size, how big would the placenta be?

I've been quite constipated, so I'm wondering if it's my bowels shifting within my tummy & that's what the bulge is..... so attractive..... hehehehe... not really!

Is anyone else around 5-6 weeks and showing yet?