I nearly jumped out of my skin.
→   거의놀라 펄쩍뛸뻔했지.

[예문]
jump out (one's) skin :놀라서 펄쩍뛰다.

A:That noise really scared you, didn't it?
  그소리가 날진짜 놀라게 했지. 그렇지않니?

B:Yes, I nearly jumped out of my skin.
  그래.거의놀라 펄쩍 뛸뻔했지.