1.Nervous and jittery
2.Blood ran cold
3.His heart,his lungs and all his youthful muscles were(are) fighting,struggling to keep him alert
4.Adrenaline gushed out from his throat
5.His emotion was greatly disturbed by consternation,concern and deep fear
6.Butterflies seemed to be flying randomly all around in my stomach
7.With a fast-beating heart and heavy footsteps
8.My mind was entirely engulfed by deep fear as........
9.Their screams added to the confusion
10.I jumped out of my skin as....(I saw something)
11.My heart was thumping faster as though it was trying to breakthrough my ribs