Painful contractions. The standard is painful contractions that are every 2-3 minutes and have been coming that frequently for at least an hour, getting closer together and longer. If you have contractions that don't quite fit the pattern and are making you miserable that is probably labor. Check with your provider for when to go to the hospital.
Labor pains. One factor that diagnoses labor pain---labor pains are repititive after fixed interval of time. The intensity of pains increases gradually, similarly the interval between the pains decreases gradually.
Pain, bleeding. Some signs of early labor include bleeding, discharge, or pain.
Contractions that ar. Are regular, or a shortening cervix, or sometimes an increase in vaginal discharge or seeing a premature bloody show, please call your OB if u are worried as your OB would want to know so u can be evaluated to make sure u are not or to be treated if u are, so u do not deliver early, so call your OB now.