Final answer:
The adverb in the sentence is 'well.'
Step-by-step explanation:
The adverb in the sentence is well.
An adverb is a word that modifies a verb, an adjective, or another adverb. In this sentence, the word 'well' is modifying the verb 'feel' by indicating how the person feels.
For example, if we replace 'well' with another adverb like 'terribly', the sentence would be 'After being sick all week, I feel terribly.'