Did i have atrial fib. or heart trouble? i'm scared. my heart/chest vibrated, i felt weird, & cold flush. was this a panic attack, or a heart problem?

Usual suspect: Anxiety is the likely suspect. Especially at your age w/ your medical history. If youthful cardiovascular problems are in your family history you'd know and should be examined, or if it's part of a syndrome you suffer - like Marfan's - you'd be being monitored for heart issues regularly already. It's a good idea to consider CBT therapy for skills in dealing w/ issues like anxiety, OCD. It works!