Am I having panic attacks?

Ever since I started university (I'm in my first year) I have been struggling with anxiety. Often times when I'm in the labs I begin to panic and think in my head that I have picked the wrong course and screwed my life up. I sometimes feel like crying in the labs and have cried before it in the past. In these situations, I feel like I have failed both in my life choices and the practical in the labs. I don't really know how to put it other than I feel terrible when I'm like this. Despite this, I never show any physical symptoms of anxiety, no sweating, no trembling, no rise in heart rate (though I don't think I'd be able to tell if this did happen so I'm unsure on this one), no nausea, no dizziness, nothing. I feel like no one professional takes me seriously because I don't react the way they think I should when feeling that kind of way. I've never known myself to exhibit these kind of symptoms even when I've been incredibly afraid, only crying and fidgeting. Is it possible that I just don't respond to intense feelings of anxiety like everyone else? Am I having panic attacks or am I just making a big deal out of nothing?