when do I know it's time?!

Had my 39 week appt today and I was barely 1 cm. Same as last week 😔 I have an irritable uterus so I have contractions pretty regularly and never really know when to take them seriously. I haven't gone in or called at all through these last few weeks because I don't want to be that person. What should I feel when it's time to go in? I'm praying my water breaks so I know for sure lol