contractions questions

Cierra
So Tuesday and Wednesday I woke up with contractions 1-3 minutes apart and went to the hospital to stop them because I'm only 31 weeks as of tomorrow. Lost my mucus plug Tuesday as well and am already 50% effaced and a fingertip dilated. They gave me steroid shots to mature the baby's lungs and muscle relaxer pills to keep contractions at minimum. 
All is going well but I'm afraid that I'm having contractions I can't feel now. 
I can put my hand on my belly and it feels hard all over just like the contractions before, but I don't feel the tightening in my stomach unless the contraction is pretty strong. I'm worried now that I won't be able to tell when my contractions start coming back in case I have to go back to the hospital. 
Does anyone have any tips on how to determine contractions better? And don't just say "you'll know when they're real" because I didn't think they were real when I went to the hospital on Tuesday but they were definitely real. I just don't want to accidentally ignore the contractions and go into the hospital too late to stop them again.