Panic attacks are caused by psychological factors, but the actual attacks themselves can manifest themselves in a physical manner - vomitting, dizziness, headaches, knotted stomach etc. If you do get them, I would advise you to talk to someone about them, whether it's professional or just someone you can trust - just sharing your anxiety will possibly help you to get over them. Also, don't feel ashamed about them or guilty. I had them a few years back and eventually spoke to someone about them and that was enough to start me on the road to recovery. Panic attacks are an illness, and you can and should get them treated.