bundle of nerves

a bundle of nerves
a ball of nerves
a bag of nerves
{infml} (someone who is extremely anxious, nervous, or tense) — комок нервов; сам не свой от беспокойства

Example 1:I was a bundle of nerves before my dental appointment / before the test / before the interview/etc.

Example 2: You always seem to be such a bundle of nerves. (thefreedictionary.com)

Example 3: She chain smokes, never sits still and is always giving little coughs. She really is a bag of nerves.

Example 4: When her relationship started getting serious, she became a bag of nerves. (OALD)

Example 5: Sorry for shouting - I'm a bundle of nerves these days. (CALD)

More examples:

..... I must give a special mention to the Duty Manager Mark. I was a bag of nerves until he came and found me. He took me through the order of the day and ran through every minor detail. Immediately I felt relaxed and confident that the day would go exactly as planned. He doesn't impose but always seems to be there when you need him. The team of porters were also fantastic.

[комок нервов]