Could I be farther along?

I have been having pre term contractions for the past few weeks... i'm 29 weeks right now and before I became pregnant I was 100 pounds ( i dont know if that makes a difference) but anyway, since no medications are helping the doctor tol me I probably won't make it to 34 weeks. So its been really bugging me lately with how much she will weigh, the whole pregnancy she has been measuring bigger, like her weight has been 2 weeks in advance, at 28 weeks the ultrasound tech said she was around 2.9 pounds. Could I be farther along? And if so if they're telling me i wont make it past 34 weeks does that mean it would be like 32 weeks if I am farther along? Please help! STRESSED!