Stomach Tight While Standing/Walking?

Stevie • Married💍 11.24.18 3.26.17 👼🏼 EVR

I’m almost 27 weeks but have been measuring a week or so ahead for awhile. Over the past couple days any time I’m standing or walking my stomach is firm to the touch and slightly uncomfortable. I started feeling this a little a few weeks ago but whenever I would sit it would go away. Now I only get relief when I lie down on my back slightly propped up, which I can only do for so long. Everyone that touches my belly makes a comment about how hard it is. I’d assume as you got closer to your due date and run out of room it would be firm then but seems a bit early? Anyone else experiencing this? I wasn’t small before pregnancy, but also not quite considered plus sized either.