A clinical diagnosis of depression is sort of a big deal in terms of what you may be allowed to do in job functions. I would be very careful about how you approach this, and would exercise any other options before taking what you may right now believe to be the case, and making it something that must be formally noted by a medical professional and acted upon consequently.
Don't get me wrong- if you have real, no-BS issues, then get the assistance you need. I draw no distinction between physical and mental injuries. But recognize that there will be consequences for you as a result of it, because it wouldn't be safe for the CF not to follow certain courses of action.