What do contractions feel like?

I’ve had Braxton Hicks a lot so I know what they feel like. But what about early labor contractions? Or full on contractions feel like? Does your stomach get tight during those as well or is it just extreme cramping? I’ve had dull cramping all day long in my lower back and lower stomach. but it’s constant & not in waves so I don’t think they’re contractions. But I’m a first time mom so I don’t really know😅. Could anyone explain what they feel like? :)