"Don't tell me what to say. If you feel like crap, it is your problem. Don't make it about my compliment to you."
Why isn't this telling him how he feels? How is it validating?
Well, he just told you he didn't feel good -- "I am not good."
How is it validating? -- you acknowledge what he said.
But, it could be done better, no doubt. My concern there was to try to get YOU to keep from swallowing his crap.
How about:
"It sounds like you don't feel good for some reason. That sucks. But, I'm sure you aren't making it about my compliment to you. So, I will choose not to be hurt by your reaction to it. I have a shoulder if you need one."
Then leave and go do something that makes you feel good.
