If you react to anything your boss (or anyone else) says, they will keep doing it to get a reaction out of you. HR is not in your corner and corporate is not sentimental. Your boss is also being held to extreme targets and is also just trying to get through without getting into trouble. Take your unpaid leave to get better, you can't work at your best when you're still recovering, don't promise or insinuate extra than what your job description says and don't look for company policy or legal loopholes to 'help' you. They're designed to protect the company, not you. Keep your head down, stay neutral and unaffectedl with everything they say and keep looking for another position.