It does sound like an anxiety attack and they can be horrendous. See a doctor because, until you either learn to control them or they are controlled by medication, they can hit at any time. You don't even have to be stressed by anything for one to just sandbag you. You may be having trouble feeling as though you can't fill your lungs either because your muscles are tense or because you are not exhaling fully. Listen to the good advice you are reading here, whatever it is, you need to see a doctor.