what do contractions feel like?

I had some braxton hicks at around 29 weeks when my stomach tightened up. Are actual contractions the same type of feeling. I am 37 weeks and when I wakened this morning I had cramping in my stomach and wondered if this may have been related to contractions. Baby is fine as I have felt her all of today. No bleeding etc. I'm not worried, just curious :) 
Maybe I worded this wrong. I've read sometimes cramping can be the sign of labour starting / pre-labour:)