Hi Jodie
It could possibly be just bloating, it is a common sympton in early pregnancy.
I was bloated up until around 10 weeks where myself and DH started noticing that my tummy was starting to change shape.
It's only been these last few weeks that I've really started to noticeably show, anyone who knew me could tell from around 18 weeks, however it's only now that strangers are starting to look at my "bump".
I suppose I'm really not that big for 24 weeks
Good luck with the rest of your pregnancy and enjoy having a little tummy, trust me!!