Had abrupt chest pains, sweating, nausea/diarrhea, and shortness of breath. skin was clammy and heart was beating fast. what could it have been?

Chest pain: Many possibilities but one of them is pulmonary embolus and you need to be evaluated rapidly for that possibility. If it turns out to be significantly less serious that's great. Go and get seen..........

Were you upset?: Feeling better? If yes, you were emotionally upset. However, if it is not related to your emotions, and it keeps happening to you, go to the nearest emergency room! good luck to you!