Afib is when your heart rate goes over 140 correct? Just wondering cause i noticed when i work out and run, my heart rate goes up to 120ish. And i woke up from a intense dream and my heart was doing the same, that is cause from adrenilne right?

Yugo,

Afib and aflutter involve heart rates mush higher that are sustained even during periods of rest. They can EASILY be spotted on an ECG.
What you are experiencing is a normal response to sustained aerobic excercise and from an adrenaline rush from a scare...both perfectly normal.

(Imagine the fright of a several minute bout with 250 BPM...a friend of mine gets that.)