I have that same heavy AF type pain you are describing hun but I remember kinda feeling this way on the boys so am hoping it's all good. I'm assuming it's everything stretching already, our bodies have done it before so I'm assuming it happens that bit earlier (hoping that's the case anyway!!)
My appetite is MASSIVE and I am sooooo bloated! And the flatulence....it's woefully embarrassing at the moment!! Today DS1 looked at me in disgust and says "Mommy go take a poo!" Please tell me this is normal and I'm not alone!!! Probably not helped by the fact I want to eat my weight in vegetables lol!!