How can i tell if i just had a panic attack?

Simple: U will feel (unmatched to the circumstace ) anxiety and feel palpitation, fearful that some thing bad can happen, scream, breath short shallow and rapd, sweat, stiff, restless...

Panic attack: Panic attacks can develop rapidly ; include: marked anxiety; rapid, pounding heart beat; chest tightness or pain; shortness of breath with hyperventilation; hot or cold flashes; a sense of butterflies in the stomach, nausea or even vomiting; tingling of mouth or extremities; increased sweating; feeling faint or lightheaded; headache or shaking. There may be difficulty swallowing or tight throat;.