What’s the difference?

How will I know the difference between Braxton Hicks, “real” contractions, and the baby pushing his whole body really hard against my abdomen?

I’m 37 weeks and I’ve been cramping since yesterday and my stomach keeps getting really tight every so often but it’s just a big spot on my stomach, not like the whole entire thing.

I have no idea what to expect or what it feels like or when to think labor is actually starting! TIA