I did this rotation back in the summer of 2003 and it sounds as is if nothing has changed. It is certainly demoralizing to be told you are worthless but at least you are getting a decent IM experience.Take it from somebody who is in an IM residency right now, the pathology you see there and the autonomy you have will hold you in good stead down the road. Consider the alternative, you could be at Wyckoff doing IM.
Good luck and keep your head up!!