I honestly don't know what to write!
I have wave like mild contractions. I don't get period pain so can't compare. I didn't get far in labour before a c section but what I did have wasn't too painful. More like waves of intense pressure. Some thick dark blood with clots but am passing in the loo (but that often happens with periods).
We don't talk about this kind of thing enough for me to know what on earth is going on!