2 cm - every cm helps

I found out this afternoon that I am 2 cm dilated and 50% effaced. I was encouraged that my contractions and pain the last several days have been doing something. Usually I don't know when I am in real labor because I have so much preterm labor. With 3 out of 5 of my babies, my Physicians Assistant has had to tell me that I was at 5 cm and in labor and to get to the hospital (the other 2 were induced). You would think I should know by now. My doc said I probably have a week before delivering - I am not getting my hopes up. Joanna was 5 days late!