Sense of calmness in meditation, what is it?

In a first 10 day vipassana meditation course I did almost continuous intensive meditation for 7 days ,I felt a strange calmness such that I could almost not feel the weight of my body , this feeling lasted till 2-3 days and then I stopped doing it, So what is that feeling called and is it common after meditation? Also after I resumed the meditation then I could not get back the same feeling (nor was I seeking for it).