Here are a few rhymes for lonely that could have negative or sad connotations:
And some near-rhymes:
It depends what you mean by "sad". There are no words that rhyme with over that are synonyms of sad. But here are some words/phrases with a sad connotation:
looked over
pushover
game over
Dreary.
Dreary
Pagod means weary.
The word you are looking for is "guava".
Tame may be the word you're looking for.
The word you're looking for is 'fleece'.
The word you're looking for is 'choir' - pronounced 'kwire'
Tire
exhausted
The word that means and rhymes with cloak is "joke."
weary
The word "afraid" slant rhymes with the word "away" but means scared.
The word that means kneel and rhymes with melt is "knelt."
It doesn't quite rhyme with "corn". The word you are looking for is spawn.