Braxton hicks are too early...Help!!?

Ok last night and right now I keep getting some Braxton Hicks.Well everytime I get one I feel like the wind is knocked out of me.They aren't painfu but I can't breath.My back will hurt but thats about it.They aren't close together or anything but geez I wish they would go away.I've done everything I can to make them go away and they won't.Right now though I have a period like cramp.This is my second and I never felt braton hicks with my son.I'm worried about pre-term labor.I'm only 24 weeks along.I do see my doctor on wednesday but what should I do in the mean time?