Here's some advice from MedHelp.org on the signs that tell you your baby is on the way. Also, some advice on when to call your OB about your symptoms. https://
www.medhelp.org/pregnancy-health/articles/7-Signs-Your-Baby-Is-On-the-Way/398
http://www.medhelp.org/pregnancy-health/articles/Serious-or-Not-When-to-Call-Your-Ob-Gyn/2208
You can also find these in the Week by Week section of the I'm Expecting app -- check Weeks 37 and 14.
Actual contractions? Or braxton hicks?
Real contractions will have you bent over in pain.
If you're having them, time them. If they're 5 minutes apart, go into the hospital