Why did Huck remain uncomfortable?

There are a few possibilities to your question in ch.30. The chapter begins with Huck knocking on the door of the Welshman, who eagerly welcomes Huck in for breakfast. The old Welshman retells the events of the night before to an anxious Huck. a lot happens to Huck in this chapter so I'd check out the following summary link:

http://www.gradesaver.com/the-adventures-of-tom-sawyer/study-guide/summary-chapters-29-35