I feel worse or I am worse.
I feel better or I am better.
It isn't clear what you mean. What does "more or less ill" mean? Tell us exactly in what situation you wish to use the sentence you have in mind.
I feel/am/get worse than yesterday because I have a higher temperature and have lost my sense of taste.
[STRIKE]Does all these phrases are good?[/STRIKE] Are they all correct?