Nick Cannon is at his wit's end over his anti-Semitic comments and his apology for them -- he clearly feels he's in a no-win situation, and now some fans are concerned about his well being. "The Masked Singer" host let his frustrations out Thursday night, saying ... "I hurt an entire community and it pained me to my core, I thought it couldn’t get any worse. Then I watched my own community turn on me and call me a sell-out for apologizing." He added ... "Goodnight. Enjoy Earth." An hour later, he followed that up, tweeting ... "Y'all can have...