mucus plug

I just lost my mucus plug and I'm 35 weeks tomorrow. So far I haven't had any type of contractions but I have been having them for about a week. My doctor said to go in if I have completely unbearable pain or if my contractions follow the 511 rule. I'm still concerned though. My son was born at 34 weeks. Am I going to be okay? I have roughly 37 days left.