Depends which part of labour changes the feeling of contractions! Pre labour is period pain and a sore lower back. Then as they increase and last longer it's a more intense cramping pain and your tummy tightens with each one! Then as you need to push it feels less period type and more just a relief as your pushing and a nicer gap in between them once pushing starts too!
Definitely don't fight them, just go with your body and it all feels right :-)