Can't decide what symptom this is.

This is my second pregnancy since miscarring back in October 2015. I'm 5w2D pregnant, I get this feeling that feels like heartburn or indigestion very often. Also when this happens I have burped/thrown up in my mouth. Is this a fourm of being nauseous because I'm really not sure what It is? I don't feel that uncomfortable with it, yes it's nerve-wracking to deal with it. Just wanted to know what it was.