Definitely see a GP. Not because I think it's not an anxiety attack, but because you really shouldn't assume it is until the doc's ruled other things out. Especially if this is new and sudden. Wouldn't hurt to get an EKG or a stress test at the very least. Probably should be standard for all new-onset panic attacks anyway.

The feeling of the stomach rising up with panic symptoms is also a symptom of a temporal lobe seizure or aura. Just saying. IANAD though.