回复：我自己感覺不好, 也不知道該寫什麼好.

Why not? There is no lose to write the thank-you letter.

First, thank the time the interviewer spending with you and get the chance to know you.

Second, emphasize several points your skills match the position and you can make contributions to the company.

Third, ask them what the next step is and when you can expect to hear from them.