Labor contractions and frequency

mjeg30

I think I am in the early stage of labor. I started with contractions yesterday at 4 am, but wasn't effaced at all at my drs apt yesterday morning. The contractions kept happening during the day yesterday, but started more frequently last night and they are still going on. I have also been losing my mucus plug throughout the morning. I have yet to sleep bc the contractions wake me. 

 

Anyway, they have been between 7 and 13 mind. Is this normal or should all of them be 7 (or whatever the time is). Can they range?