I've had this sensation before, and it's becoming more common for me unfortunately. I had awful anxiety this morning on the way to school, despite being fine when I woke up and having a pretty good first week of college. As soon as we got into the city, all at once I felt like I couldn't breathe, my chest tightened, my stomach tightened, and I felt like I wanted to hurl. Plus my friend's guy friend was driving, and he has a heavy foot and was passing cars left and right, so that just added to my anxiety.
I don't know how I even got over that this morning (or how I managed not to throw up), it just went away once I got into psychology. It was weird.