How can I?

I’ll be 37 weeks on Wednesday (tomorrow). Well, I haven’t really paid attention to my body as much as I should, I know probably a bad mother. But if I paid attention I’d be worried about every single tiny thing. Anyways, how am I suppose to know when my stomach is tightening? My stomach is constantly hard when I touch it. So I’m confused when they say to feel when your stomach tightens and the releases because my stomach is always hard .