Randomly hard to breathe and almost pass out - 21 weeks

Hi, have any of you experienced shortness of breath out of nowhere? Like the kind where you can't seem to breathe in enough and the you get really dizzy and almost pass out? I have had this happen twice now. The latest one was last night and it got so bad my husband went out to start the car to bring me to the hospital. Then all of the sudden I puked everywhere and was fine. Should I call my dr or is this common?