Personally I wouldn't say anything more to the professor/department chair, at least not unless there is a specific reason why they'd need to know. It might be more beneficial to find a new therapist who can work through these issues with you, something you definitely need in order to complete a masters program in psych. It's especially important to have this support before and while you are interning (and beyond if necessary). Regarding why you want to drop out of the program, can you talk to an advisor about this?