If it's a contraction, you'll feel your uterus harden.
Trust your instincts! I thought I was just having braxton hicks contractions because everyone told me how painful contractions were and mone werent that bad but they ended up being true contractions and I was 4cm before my coworkers made me go to labour and delivery.
It depends on the time any where from 1-5
Call ur doc if ur in pain on a scale 1-10 how u feel